From e01e98e78d4aa0a6dc39a73bcaf7892e95855ebb Mon Sep 17 00:00:00 2001 From: Tom Nisbet Date: Fri, 17 May 2024 12:42:43 -0400 Subject: [PATCH] split PromDevice docs to separate pages --- docs/_docs/prom-500-pd27.md | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/docs/_docs/prom-500-pd27.md b/docs/_docs/prom-500-pd27.md index 013af3d..0809cda 100644 --- a/docs/_docs/prom-500-pd27.md +++ b/docs/_docs/prom-500-pd27.md @@ -18,7 +18,7 @@ Chips that use high voltage pulses for each byte are not supported. For those c |:--- |:--- |:--- |:--- |:--- | |[M27256](#m27256) |ST Micro |EPROM |27 |VCC=6V, VPP=12.5V to pgm| |[M27C256](#m27c256) |ST Micro |EPROM |27 |VCC=6.5V, VPP=12.75V to pgm| -|[W27C257](#w27c257,-27e257,-27c512) |Winbond |EEPROM |27 |Continuous 12V or 14V for program/erase| +|[W27C257](#w27c257-27e257-27c512) |Winbond |EEPROM |27 |Continuous 12V or 14V for program/erase| |[SST27SF020](#sst27sf020)|SST |Flash |27 |12V continuous for pgm/erase| @@ -46,7 +46,7 @@ The Winbond W27C257 and W27E257 appear to be identical 32Kx8 EEPROMs. The 27C v The 257 EEPROMs have a _VPP_ pin that needs a constant 12V during programming. Unlike the newer 28C EEPROMs, these chips do not automatically erase before writing to a location. Instead, the entire chip is erased by applying 14V to _VPP_ and _A9_ and then pulsing _CE_. To erase the chip, assert the voltages on _VPP_ and _A9_ and then issue the _Erase_ command from the terminal. -Unlike the 257 chips, the W27C512 does not have a dedicated pin for the programming voltage and instead uses the 12V on _OE_ pin to place the chip in programming mode. The verify operation requires that the _OE_ pin be switched to _LOW_ and there is no hardware support for this, so the current code supports the 512 chip by doing a single write cycle with no verify. +Unlike the 257 chips, the W27C512 does not have a dedicated pin for the programming voltage and instead uses 12V on the _OE_ pin to place the chip in programming mode. The verify operation requires that the _OE_ pin be switched to _LOW_ and there is no hardware support for this, so the current code supports the 512 chip by doing a single write cycle with no verify. Because the chips use a constant high voltage for programming instead of a pulse, an external power supply and two diodes can be used to supply either 5V or 12V to the pins for programming and erasing. @@ -54,15 +54,9 @@ Note that the W27x257 chip are almost a drop-in replacement for the 28C256. The ## SST27SF020 -The Silicon Storage SST27SF0x0 are programmed similarly to the 27C257 in that a constant -voltage is applied for program and erase operations. Unlike the 27C257, these have a -dedicated WE pin that controls programming and erasing. Another difference is that they -do not have a verify operation to read back the programmed data. +The Silicon Storage SST27SF0x0 are programmed similarly to the 27C257 in that a constant voltage is applied for program and erase operations. Unlike the 27C257, these have a dedicated WE pin that controls programming and erasing. Another difference is that they do not have a verify operation to read back the programmed data. -These Flash chips have a _VPP_ pin that needs a constant 12V during programming. Unlike -the newer 28C EEPROMs, these chips do not automatically erase before writing to a -location. Instead, the entire chip is erased by applying 12V to _VPP_ and _A9_ and then -pulsing _WE_. +These Flash chips have a _VPP_ pin that needs a constant 12V during programming. Unlike the newer 28C EEPROMs, these chips do not automatically erase before writing to a location. Instead, the entire chip is erased by applying 12V to _VPP_ and _A9_ and then pulsing _WE_. ## Chips to be Tested