Git-Mirrors
/
tillitis-key
mirror of https://github.com/tillitis/tillitis-key1.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Adding information about the SPI-master including API 

and protocol, the memory type, and where to find the
datasheet form the memory.

Signed-off-by: Joachim Strömbergson <joachim@assured.se>
This commit is contained in:
Joachim Strömbergson 2024-02-12 13:38:07 +01:00
parent 50f3e53a03
commit 5509be0eaa
No known key found for this signature in database
GPG Key ID: 865B8A548EA61679
1 changed files with 54 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
hw/application_fpga/core/tk1/README.md
View File

@ -169,6 +169,59 @@ core will detect that and start flashing the RGB LED with a red
light - indicating that the CPU is its trap state and no further
execution is possible.
## SPI-master
The TK1 includes a minimal SPI-master that provides access to the
Winbond Flash memory mounted on the board. The SPI-master is byte
oriented and very minimalistic.
In order to transfer more than a single byte, SW must read status and
write commands needed to send a sequence of bytes. In order to read
out a sequence of bytes from the memory, SW must send as many dummy
bytes as the data being read from the memory.
The SPI-master is controlled using a few API
addresses:
```
localparam ADDR_SPI_EN = 8'h80;
localparam ADDR_SPI_XFER = 8'h81;
localparam ADDR_SPI_DATA = 8'h82;
```
**ADDR_SPI_EN** enables and disabled the SPI-master. Writing a 0x01 will
lower the SPI chip select to the memory. Writing a 0x00 will raise the
chip select.
Writing to the **ADDR_SPI_XFER** starts a byte transfer. Reading from
the address returns the status for the SPI-master. If the return value
is not zero, the SPI-master is ready to send a byte.
**ADDR_SPI_DATA** is the address used to send and receive a byte.
data. The least significant byte will be sent to the memory during a
transfer. The byte returned from the memory will be presented to SW if
the address is read after a transfer has completed.
The sequence of operations needed to perform is thus:
1. Activate the SPI-master by writing a 0x00000001 to ADDR_SPI_EN
2. Write a byte to ADDR_SPI_DATA
3. Read ADDR_SPI_XFER to check status. Repeat until the read
operation returns non-zero value
4. Write to ADDR_SPI_XFER
5. Read ADDR_SPI_XFER to check status. Repeat until the read operation
returns a non-zero value
6. Read out the received byte frm ADDR_SPI_DATA
7. Repeat 2..6 as many times as needed to send a command and data to
the memory and getting the expected status, data back.
8. Deactivate the SPI-master by writing 0x00000000 to ADDR_SPI_EN
The SPI connected memory on the board is the Winbond W25Q80. For
information about the memory including support commands and protocol,
see the datasheet:
https://www.mouser.se/datasheet/2/949/w25q80dv_dl_revh_10022015-1489677.pdf
## Implementation
@ -179,7 +232,7 @@ probably be separated into separate modules.
## Winbond Flash memory model
The testbench for the SPI master includes a memory model of the Flash
memory. The model is provided by Winbond and the copyright for the
memory. The model is provided by Winbond and the copyright for the
model is:
```