This is a simulated ATMEL AT29 or AMD Am29 series flash memory. It can be configured to emulate any of the AT29 or Am29 family members.
Memory operations such as programming and erasing are achieved instantly in simulation. As such, device facilities for performing in-progress operations such as suspending and resuming erase operations are not implemented.
Hardware sector protection is not implemented.
In the actual hardware, the ATMEL flash memory has timing sensitivities when programming sectors. During such programming, the final byte that is modified in a sector is set to an incorrect value until the programming has been completed. In simulation, the programming of a sector appears to be instantaneous. Therefore, it may not be possible to detect software programs that are not sensitive to the timing requirements in real hardware.
In AMTEL components, the data security facility that prevents the memory from being inadvertently modified in the presence of bus transients, has a similar restriction that forces data writes to be performed in rapid succession. If an interval elapses, data security is re-enabled and the unlocking code sequence must be reissued (see ``References'' for more details).
| Behaviors | |
|---|---|
| configuration |
Flash memory chips are self-describing using their device-code and manufacturer-code values, accessible both to a target program, and to the simulator user via attributes. Since a target program may infer memory size from these values, further simulation configuration that overrides these values should be avoided unless necessary. The device-code attribute represents the device code of the flash memory part being simulated. Refer to the ATMEL or AMD data sheet for a complete list of device identification codes. The manufacturer-code read-only attribute represents the manufacturer code of the flash memory. It is a constant value for ATMEL and AMD. The sector-size attribute specifies the size of an individual sector in the flash memory. Typical values are 64 to 512 bytes. When the size attribute is written-to with a legal value, a new cleared byte array is allocated with the new size. The old byte array is thrown away. The size-max read-only attribute supplies to the user the maximum size that this component will attempt to allocate. |
| image save/load |
When the image-load pin is driven, this component will open and attempt to load the contents of the file given by the image-file attribute into the memory image. The file is copied byte-for-byte. If the file is too short, zeroes are used to fill out the rest of the memory. Similarly, when the image-store pin is driven, the component will write to the image-file file a byte-for-byte dump of the entire memory image. |
| reading/writing |
When an access is received on the read-write-port bus, the component checks the incoming address and rejects it if out-of-range. The component also rejects non-byte-sized accesses. Memory can be read at will, but for the AMD models, AMD's protocol must be followed to put the device into byte program mode or unlock bypass mode. The mode read-only attribute reveals the internal state of the device state machine. This is primarily designed for testing purposes. For AMTEL models, the data security protocol must be followed when writing to the memory - see ATMEL documentation. |
| memory latency |
The component models the effects of memory latency. The read-latency and write-latency values specify the latencies for memory reads and writes, respectively. |
| SID Conventions | ||
|---|---|---|
| functional | supported | - |
| latency | supported | The component models memory latency. |
| save/restore | supported | The component supports saving and restoring state in addition to memory persistence, via the image-store pin/attribute. |
| triggerpoints | not supported | - |
Related components
Customized versions of this component are available for standard members of the AT29 flash family. Instantiating each of them is equivalent to instantiating this generic component and setting the appropriate sector-size, size, and device-code attribute settings.
A flash memory will usually form a small part of the complete memory subsystem, providing a region of non-volatile memory. The following configuration file fragment demonstrates this:
new hw-mapper-basic bus new hw-memory-flash-at29lv040 flash # AT29LV040: 512KB size, 512 sector-size connect-bus bus [0,0x7FFFF] flash read-write-port
The memory is modelled as a contiguous array of bytes in host memory. As such, a component configured for 8MB of memory requires 8MB of host memory. This is an important consideration for simulations running on machines with low memory or on busy multiuser systems. Similarly, when a memory image is written to disk, the same amount of space may be used there.
| pins | |||
|---|---|---|---|
| name | direction | legalvalues | behaviors |
| image-load | in | any | image load/store |
| image-store | in | any | image load/store |
| buses | |||
|---|---|---|---|
| name | addresses | accesses | behaviors |
| read-write-port | 0 .. size-1 | byte-wide access only | |
| attributes | |||||
|---|---|---|---|---|---|
| name | category | legal values | default value | behaviors | |
| device-code | setting | 0 .. 0xFF | 0x5B | configuration | |
| manufacturer-code | setting | 0x1F | 0x1F | configuration | |
| size | setting | numeric | 524288 | configuration | |
| size-max | setting | numeric | fixed at 32MB | configuration | |
| sector-size | setting | numeric | 512 | configuration | |
| image-file | setting | filename | - | image save/load | |
| read-latency | setting | numeric | 0 | memory latency | |
| write-latency | setting | numeric | 0 | memory latency | |
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
| attributes | |||||
|---|---|---|---|---|---|
| name | category | legal values | default value | behaviors | |
| mode | - | 0 .. 9 | 0 for read mode | reading/writing | |
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
Same as hw-memory-flash-atmel
AMD Am29 series data sheets, application notes, ATMEL AT29 series data sheets, application notes.