OVP Virtual Platform: AtmelAT91SAM7
This page provides detailed information about the OVP Virtual Platform Model of the
atmel.ovpworld.org AtmelAT91SAM7 platform.
Description
Simple platform of Atmel AT91 ARM7TDMI based system
Limitations
This platform is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
Licensing
Open Source Apache 2.0
Location
The AtmelAT91SAM7 virtual platform is located in an Imperas/OVP installation at the VLNV: atmel.ovpworld.org / module / AtmelAT91SAM7 / 1.0.
Platform Summary
Table : Components in platform
Processor [arm.ovpworld.org/processor/arm/1.0] instance: ARM7TDMICore
Processor model type: 'arm' variant 'ARM7TDMI' definition
Imperas OVP processor models support multiple variants and details of the variants implemented in this model can be found in:
- the Imperas installation located at ImperasLib/source/arm.ovpworld.org/processor/arm/1.0/doc
- the OVP website:
OVP_Model_Specific_Information_arm_ARM7TDMI.pdfDescription
ARM Processor Model
Licensing
Usage of binary model under license governing simulator usage.
Note that for models of ARM CPUs the license includes the following terms:
Licensee is granted a non-exclusive, worldwide, non-transferable, revocable licence to:
If no source is being provided to the Licensee: use and copy only (no modifications rights are granted) the model for the sole purpose of designing, developing, analyzing, debugging, testing, verifying, validating and optimizing software which: (a) (i) is for ARM based systems; and (ii) does not incorporate the ARM Models or any part thereof; and (b) such ARM Models may not be used to emulate an ARM based system to run application software in a production or live environment.
If source code is being provided to the Licensee: use, copy and modify the model for the sole purpose of designing, developing, analyzing, debugging, testing, verifying, validating and optimizing software which: (a) (i) is for ARM based systems; and (ii) does not incorporate the ARM Models or any part thereof; and (b) such ARM Models may not be used to emulate an ARM based system to run application software in a production or live environment.
In the case of any Licensee who is either or both an academic or educational institution the purposes shall be limited to internal use.
Except to the extent that such activity is permitted by applicable law, Licensee shall not reverse engineer, decompile, or disassemble this model. If this model was provided to Licensee in Europe, Licensee shall not reverse engineer, decompile or disassemble the Model for the purposes of error correction.
The License agreement does not entitle Licensee to manufacture in silicon any product based on this model.
The License agreement does not entitle Licensee to use this model for evaluating the validity of any ARM patent.
Source of model available under separate Imperas Software License Agreement.
Limitations
Instruction pipelines are not modeled in any way. All instructions are assumed to complete immediately. This means that instruction barrier instructions (e.g. ISB, CP15ISB) are treated as NOPs, with the exception of any undefined instruction behavior, which is modeled. The model does not implement speculative fetch behavior. The branch cache is not modeled.
Caches and write buffers are not modeled in any way. All loads, fetches and stores complete immediately and in order, and are fully synchronous (as if the memory was of Strongly Ordered or Device-nGnRnE type). Data barrier instructions (e.g. DSB, CP15DSB) are treated as NOPs, with the exception of any undefined instruction behavior, which is modeled. Cache manipulation instructions are implemented as NOPs, with the exception of any undefined instruction behavior, which is modeled.
Real-world timing effects are not modeled: all instructions are assumed to complete in a single cycle.
Verification
Models have been extensively tested by Imperas. ARM7TDMI models have been successfully used by customers to simulate ucLinux on Atmel virtual platforms.
Features
The precise set of implemented features in the model is defined by ID registers. Use overrides to modify these if required (for example override_PFR0 or override_AA64PFR0_EL1).
Core Features
Thumb instructions are supported.
Debug Mask
It is possible to enable model debug features in various categories. This can be done statically using the "override_debugMask" parameter, or dynamically using the "debugflags" command. Enabled debug features are specified using a bitmask value, as follows:
Value 0x080: enable debugging of all system register accesses.
Value 0x100: enable debugging of all traps of system register accesses.
Value 0x200: enable verbose debugging of other miscellaneous behavior (for example, the reason why a particular instruction is undefined).
All other bits in the debug bitmask are reserved and must not be set to non-zero values.
AArch32 Unpredictable Behavior
Many AArch32 instruction behaviors are described in the ARM ARM as CONSTRAINED UNPREDICTABLE. This section describes how such situations are handled by this model.
Equal Target Registers
Some instructions allow the specification of two target registers (for example, double-width SMULL, or some VMOV variants), and such instructions are CONSTRAINED UNPREDICTABLE if the same target register is specified in both positions. In this model, such instructions are treated as UNDEFINED.
Floating Point Load/Store Multiple Lists
Instructions that load or store a list of floating point registers (e.g. VSTM, VLDM, VPUSH, VPOP) are CONSTRAINED UNPREDICTABLE if either the uppermost register in the specified range is greater than 32 or (for 64-bit registers) if more than 16 registers are specified. In this model, such instructions are treated as UNDEFINED.
Floating Point VLD[2-4]/VST[2-4] Range Overflow
Instructions that load or store a fixed number of floating point registers (e.g. VST2, VLD2) are CONSTRAINED UNPREDICTABLE if the upper register bound exceeds the number of implemented floating point registers. In this model, these instructions load and store using modulo 32 indexing (consistent with AArch64 instructions with similar behavior).
If-Then (IT) Block Constraints
Where the behavior of an instruction in an if-then (IT) block is described as CONSTRAINED UNPREDICTABLE, this model treats that instruction as UNDEFINED.
Use of R13
In architecture variants before ARMv8, use of R13 was described as CONSTRAINED UNPREDICTABLE in many circumstances. From ARMv8, most of these situations are no longer considered unpredictable. This model allows R13 to be used like any other GPR, consistent with the ARMv8 specification.
Use of R15
Use of R15 is described as CONSTRAINED UNPREDICTABLE in many circumstances. This model allows such use to be configured using the parameter "unpredictableR15" as follows:
Value "undefined": any reference to R15 in such a situation is treated as UNDEFINED;
Value "nop": any reference to R15 in such a situation causes the instruction to be treated as a NOP;
Value "raz_wi": any reference to R15 in such a situation causes the instruction to be treated as a RAZ/WI (that is, R15 is read as zero and write-ignored);
Value "execute": any reference to R15 in such a situation is executed using the current value of R15 on read, and writes to R15 are allowed (but are not interworking).
Value "assert": any reference to R15 in such a situation causes the simulation to halt with an assertion message (allowing any such unpredictable uses to be easily identified).
In this variant, the default value of "unpredictableR15" is "execute".
Unpredictable Instructions in Some Modes
Some instructions are described as CONSTRAINED UNPREDICTABLE in some modes only (for example, MSR accessing SPSR is CONSTRAINED UNPREDICTABLE in User and System modes). This model allows such use to be configured using the parameter "unpredictableModal", which can have values "undefined" or "nop". See the previous section for more information about the meaning of these values.
In this variant, the default value of "unpredictableModal" is "nop".
Integration Support
This model implements a number of non-architectural pseudo-registers and other features to facilitate integration.
Halt Reason Introspection
An artifact register HaltReason can be read to determine the reason or reasons that a processor is halted. This register is a bitfield, with the following encoding: bit 0 indicates the processor has executed a wait-for-event (WFE) instruction; bit 1 indicates the processor has executed a wait-for-interrupt (WFI) instruction; and bit 2 indicates the processor is held in reset.
System Register Access Monitor
If parameter "enableSystemMonitorBus" is True, an artifact 32-bit bus "SystemMonitor" is enabled for each PE. Every system register read or write by that PE is then visible as a read or write on this artifact bus, and can therefore be monitored using callbacks installed in the client environment (use opBusReadMonitorAdd/opBusWriteMonitorAdd or icmAddBusReadCallback/icmAddBusWriteCallback, depending on the client API). The format of the address on the bus is as follows:
bits 31:26 - zero
bit 25 - 1 if AArch64 access, 0 if AArch32 access
bit 24 - 1 if non-secure access, 0 if secure access
bits 23:20 - CRm value
bits 19:16 - CRn value
bits 15:12 - op2 value
bits 11:8 - op1 value
bits 7:4 - op0 value (AArch64) or coprocessor number (AArch32)
bits 3:0 - zero
As an example, to view non-secure writes to writes to CNTFRQ_EL0 in AArch64 state, install a write monitor on address range 0x020e0330:0x020e0333.
System Register Implementation
If parameter "enableSystemBus" is True, an artifact 32-bit bus "System" is enabled for each PE. Slave callbacks installed on this bus can be used to implement modified system register behavior (use opBusSlaveNew or icmMapExternalMemory, depending on the client API). The format of the address on the bus is the same as for the system monitor bus, described above.
Instance Parameters
Several parameters can be specified when a processor is instanced in a platform. For this processor instance 'ARM7TDMICore' it has been instanced with the following parameters:
Table 1: Processor Instance 'ARM7TDMICore' Parameters (Configurations)
Parameter | Value | Description |
---|
endian | little | Select processor endian (big or little) |
simulateexceptions | simulateexceptions | Causes the processor simulate exceptions instead of halting |
mips | 100 | The nominal MIPS for the processor |
semihostvendor | atmel.ovpworld.org | The VLNV vendor name of a Semihost library |
semihostlibrary | intercept | The VLNV library name of a Semihost library |
semihostname | loader | The VLNV name of a Semihost library |
Table 2: Processor Instance 'ARM7TDMICore' Parameters (Attributes)
Parameter Name | Value | Type |
---|
variant | ARM7TDMI | enum |
Memory Map for processor 'ARM7TDMICore' bus: 'mainbus'
Processor instance 'ARM7TDMICore' is connected to bus 'mainbus' using master port 'INSTRUCTION'.
Processor instance 'ARM7TDMICore' is connected to bus 'mainbus' using master port 'DATA'.
Table 3: Memory Map ( 'ARM7TDMICore' / 'mainbus' [width: 32] )
Lo Address | Hi Address | Instance | Component |
---|
0x0 | 0xFFFFF | ram0 | ram |
0x400000 | 0xFFBFFFFF | extDev | ram |
0xFFF00000 | 0xFFF03FFF | SF | SpecialFunction |
0xFFFCC000 | 0xFFFCFFFF | USART1 | UsartInterface |
0xFFFD0000 | 0xFFFD3FFF | USART0 | UsartInterface |
0xFFFE0000 | 0xFFFE3FFF | TC | TimerCounter |
0xFFFF0000 | 0xFFFF3FFF | PIO | ParallelIOController |
0xFFFF4000 | 0xFFFF7FFF | PS | PowerSaving |
0xFFFF8000 | 0xFFFFBFFF | WD | WatchdogTimer |
0xFFFFF000 | 0xFFFFFFFF | AIC | AdvancedInterruptController |
Net Connections to processor: 'ARM7TDMICore'
Table 4: Processor Net Connections ( 'ARM7TDMICore' )
Net Port | Net | Instance | Component |
---|
fiq | NFIQ | AIC | AdvancedInterruptController |
irq | NIRQ | AIC | AdvancedInterruptController |
Peripheral Instances
Peripheral [atmel.ovpworld.org/peripheral/AdvancedInterruptController/1.0] instance: AIC
Description
AIC: Advanced Interrupt Controller This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux The Advanced Interrupt Controller has an 8-level priority, individually maskable, vectored interrupt controller, and drives the NIRQ and NFIQ pins of the ARM7TDMI from: The external fast interrupt line (FIQ) The three external interrupt request lines (IRQ0 - IRQ2) The interrupt signals from the on-chip peripherals The AIC is extensively programmable offering maximum flexibility, and its vectoring features reduce the real-time overhead in handling interrupts. The AIC also features a spurious vector detection feature, which reduces spurious interrupt handling to a minimum, and a protect mode that facilitates the debug capabilities.
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/WatchdogTimer/1.0] instance: WD
Description
WD: Watchdog The Watchdog is built around a 16-bit counter and is used to prevent system lock-up if the software becomes trapped in a deadlock. It can generate an internal reset or interrupt, or assert an active level on the dedicated pin NWDOVF. All programming registers are password-protected to prevent unintentional programming. for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/PowerSaving/1.0] instance: PS
Description
This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/ParallelIOController/1.0] instance: PIO
Description
PIO: Parallel I/O Controller This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux The Parallel I/O Controller has 32 programmable I/O lines. Six pins are dedicated as general-purpose I/O pins. Other I/O lines are multiplexed with an external signal of a peripheral to optimize the use of available package pins. The PIO controller enables generation of an interrupt on input change and insertion of a simple input glitch filter on any of the PIO pins. for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/TimerCounter/1.0] instance: TC
Description
TC: Timer Counter This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux The Timer Counter block includes three identical 16-bit timer counter channels. Each channel can be independently programmed to perform a wide range of functions including frequency measurement, event counting, interval measurement, pulse generation, delay timing and pulse width modulation. The Timer Counter can be used in Capture or Waveform mode, and all three counter channels can be started simultaneously and chained together. for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/UsartInterface/1.0] instance: USART0
Description
USART: Universal Synchronous/Asynchronous Receiver Transmitter This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux. The USART has its own baud rate generator, and two dedicated Peripheral Data Controller. channels. The data format includes a start bit, up to 8 data bits, an optional programmable parity bit and up to 2 stop bits. The USART also features a Receiver Timeout register, facilitating variable length frame support when it is working with the PDC, and a Time-guard register, used when interfacing with slow remote equipment. for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
Table 5: Configuration options (attributes) set for instance 'USART0'
Attributes | Value |
---|
finishOnDisconnect | 1 |
Peripheral [atmel.ovpworld.org/peripheral/UsartInterface/1.0] instance: USART1
Description
USART: Universal Synchronous/Asynchronous Receiver Transmitter This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux. The USART has its own baud rate generator, and two dedicated Peripheral Data Controller. channels. The data format includes a start bit, up to 8 data bits, an optional programmable parity bit and up to 2 stop bits. The USART also features a Receiver Timeout register, facilitating variable length frame support when it is working with the PDC, and a Time-guard register, used when interfacing with slow remote equipment. for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.
Peripheral [atmel.ovpworld.org/peripheral/SpecialFunction/1.0] instance: SF
Description
This model contains an accurate Register set interface. The functionality has only been implemented to sufficiently boot uClinux The AT91FR40162SB provides registers that implement the following special functions. Chip Identification RESET Status Protect Mode for more information visit http://www.atmel.com/products/at91
Licensing
Open Source Apache 2.0
Limitations
This model is sufficient to boot Linux
Reference
Rev. 1354D ARM08/02
There are no configuration options set for this peripheral instance.