27 series EPROM programmer

The 27 series 28-pin EPROM programmer
 
currently supports the tested model AM27 M27 W27, with a programming voltage of 12.5v. Other manufacturers are either too expensive or unavailable
[It is known that some chips have different timings and cannot be written to, such as HN27, and some Requires 21v voltage to write, not supported]
 
Some chips require 6V to write to VCC. Some of the ones I tried above can be written with 5v voltage. Other models may not be able to write to
atmega8a. The capacity is only 8k, and the code is almost full. , only enough to read and write these chips
2764 27128 27256 27512, corresponding to the onboard boost circuit with capacities 8k 16k 32k 64k respectively
 
. The ADC is read through the 10k+2k resistor voltage division. Try to use higher precision for these two resistors, such as 1 % accuracy. A deviation of 5% would be relatively large.
When the client tests the connection, it will read the ADC return and use it to adjust the adjustable resistor (if this resistor is not connected or the contact is not good, it may burn the booster chip and scrap two pieces).
 
The code address is
https://gitee.com/ happysoul/eeprom28-new
uses arduino to upload code. You need to burn the bootloader first,
just like the 29 programmer. You can use other 32pin large-capacity atmega such as 168 328, etc. (the model cannot end with B such as 168PB).
 
The environment configuration and client python interface are with 29 chip programmers are the same, but the display model is different
https://oshwhub.com/firseve/eeprom_29
 
eprom information can be downloaded on mobile phone [Semiconductor Chip] Search chip model There are pdf
 
other chip programmers click on my avatar to see the project
other programmers throw Seafood market, consider open source in the future