From 69508f5d95637b5d59a94d788d3d32eac8b67035 Mon Sep 17 00:00:00 2001 From: Tom Nisbet Date: Tue, 19 Sep 2023 12:17:07 -0400 Subject: [PATCH] chip-specific docs --- docs/_docs/design-250-prom-specific-code.md | 24 +++++++++++++-------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/docs/_docs/design-250-prom-specific-code.md b/docs/_docs/design-250-prom-specific-code.md index db36d36..4f0a2b7 100644 --- a/docs/_docs/design-250-prom-specific-code.md +++ b/docs/_docs/design-250-prom-specific-code.md @@ -61,7 +61,8 @@ chips, allowing a 32KB chip to be programmed in just a few seconds. ## PromDeviceSST39SF -The SST39SF0x0 NOR Flash chips use fixed 4KB sectors that must be manually erased before a +SST39SF0x0 NOR Flash chips are 5V-only chips that use a command register for program and +erase operations. They use fixed 4K-byte sectors that must be manually erased before a new program operation, but the code manages this transparently. Whenever a write is started to a new segment, the driver first initiates an erase of that sector. A second write to the same sector will not cause an erase, so it is possible to write to a segment @@ -69,14 +70,15 @@ multiple times with no additional steps as long as the writes are to different p the sector. For example, 256 bytes could be written to the start of a sector from one file and then 512 bytes could be written to the end of the sector from another file. -Writing data that spans multiple sectors also works with no additional steps. When -a sector boundary is crossed, the new sector is erased and set as the current sector. +Writing data that spans multiple sectors also works with no additional steps. When a +sector boundary is crossed, the new sector is erased and set as the current sector. -The SST39SF driver supports a manual erase from the command line using the E command. -This is only needed if data will be rewritten to the same location after a previous write -to that sector. +The SST39SF driver supports a manual erase from the command line using the E command. This +is only needed if data will be rewritten to the same location after a previous write to +that sector. -All programming and erase operations for the 39SF chips require only a single 5V power supply. +All programming and erase operations for the 39SF chips require only a single 5V power +supply. ## PromDeviceSST28SF @@ -237,11 +239,15 @@ pulsing _WE_. |Model |Manufacturer |Type |Module |Notes| |:--- |:--- |:--- |:--- |:--- | -|M27C4001 |ST Micro |EEPROM | |VCC=6.5V, VPP=12.75V to pgm| +|M27C2001 |ST Micro |EPROM | |VCC=6.5V, VPP=12.75V to pgm| +|M27C4001 |ST Micro |EPROM | |VCC=6.5V, VPP=12.75V to pgm| |W27C512 |Winbond |EEPROM |27 |Continual 12V or 14V for program/erase,VPP on OE| |AM28F512 |AMD |EEPROM | || |AM29F040 |AMD |EEPROM | || -|AMS29AF010|AMS | | || +|AMS29AF010| | | || +|2764 |SEEQ |EPROM | || +|W29C040 |Winbond | | || + # Chip Manufacturers