QNICE-FPGA
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sy2002
MEGA65: HyperRAM: 16-bit write/read not stable
Using test_programs/MEGA65/hyperram.asm. What it does:
Start at address 0x00333333 and fill 1MB of data with 16-bit values starting from 0x0000 and then count them up by one at every address, so:
Address ==> Value
0x00333333 ==> 0x0000
0x00333331 ==> 0x0001
0x00333332 ==> 0x0002
[...]
0x00343332 ==> 0xFFFF
0x00343333 ==> 0x000
[...]
After filling 1MB like this, it is read. If something goes wrong, then the address where this happens, the actual value and the expected value is printed.
STEP 1: Run from a freshly programmed FPGA (means: HRAM driver and wrapper fresh)
8-bit part works, and the very first 255 words of the 16-bit part work, too. But then word number 256 and 257 have a problem. And from there on, every 256 words of the 16-bit part has errors:
16-bit linear test: Fill 1MB from 0x0333333 with 16-bit values, then test:
16-bit linear test: FAILED
Read Errors: 0x0198 (decimal: 408)
Address Actual Expected
00333433: 0000 0100
00333434: 0001 0101
00333533: 0100 0200
00333534: 0101 0201
00333633: 0200 0300
00333634: 0201 0301
00333733: 0300 0400
00333734: 0301 0401
00333833: 0400 0500
00333834: 0401 0501
00333933: 0500 0600
00333934: 0501 0601
00333A33: 0600 0700
00333A34: 0601 0701
00333B33: 0700 0800
00333B34: 0701 0801
00333C33: 0800 0900
00333C34: 0801 0901
00333D33: 0900 0A00
00333D34: 0901 0A01
00333E33: 0A00 0B00
00333E34: 0A01 0B01
[ ... output shortened, but the pattern continues every 256 bytes ...]
0033FC33: C800 C900
0033FC34: C801 C901
0033FD33: C900 CA00
0033FD34: C901 CA01
0033FE33: CA00 CB00
0033FE34: CA01 CB01
0033FF33: CB00 CC00
0033FF34: CB01 CC01
STEP 2: Re-run via C R 8000 directly after STEP 1
Similar result, but there are two more errors (410 errors instead of 408) and those two additional errors are at the very beginning.
16-bit linear test: Fill 1MB from 0x0333333 with 16-bit values, then test:
16-bit linear test: FAILED
Read Errors: 0x019A (decimal: 410)
Address Actual Expected
00333333: CC00 0000
00333334: CC01 0001
00333433: 0000 0100
00333434: 0001 0101
00333533: 0100 0200
00333534: 0101 0201
00333633: 0200 0300
00333634: 0201 0301
00333733: 0300 0400
00333734: 0301 0401
00333833: 0400 0500
00333834: 0401 0501
[ ... output shortened, but the pattern continues every 256 bytes ...]
0033FE33: CA00 CB00
0033FE34: CA01 CB01
0033FF33: CB00 CC00
0033FF34: CB01 CC01
The operative work on this issue is happening in the MEGA65 core repo:
https://github.com/MEGA65/mega65-core/issues/280