5 minute build 24XX/24CXX series EEPROM programmer (9 pin serial)

[glossywhite]

Found a VERY poor diagram of a VERY simple (and working) 24XX/24CXX series EEPROM programmer, so I re-drew it... just not AS badly . I built this in five mins flat, and it works EVERY TIME on 24 series EEPROMS, with "PonyProg" software:

[PeterG]

Looks a lot like a JDM programmer. Maybe the first version of it anyway.....

[Jon Chandler]

A true RS-232 com port has +12/-12 volt levels instead of 0/5 volt levels.  Newer computers sometimes have 5 volt versions but this circuit looks like a quick way to damage chips.

[glossywhite]

A true RS-232 com port has +12/-12 volt levels instead of 0/5 volt levels.  Newer computers sometimes have 5 volt versions but this circuit looks like a quick way to damage chips.

Well it works on my pc... can't guarantee it though.

[Mechatrommer]

A true RS-232 com port has +12/-12 volt levels instead of 0/5 volt levels.  Newer computers sometimes have 5 volt versions but this circuit looks like a quick way to damage chips.

Well it works on my pc... can't guarantee it though.

can you check your rs232 with oscilloscope? to see what voltage level is your rs232? so we will not have any chip damage report.

[alm]

IIRC the RS-232 spec is something like min. +/-3V and (absolute) max. +/-25V. Adding something like a MAX232 would probably be a good idea.

Does it work with USB-serial interfaces? I don't think all(most?) of them implement handshaking.

[glossywhite]

I don't currently have an oscilloscope - I am waiting on one from an old friend. I didn't realise the voltage spec was so broad; I must have a low voltage on my PCs COM, then.

[Mechatrommer]

I don't currently have an oscilloscope - I am waiting on one from an old friend. I didn't realise the voltage spec was so broad; I must have a low voltage on my PCs COM, then.

send something high, and measure with multimeter Vdc.

[mikeselectricstuff]

IIRC the RS-232 spec is something like min. +/-3V and (absolute) max. +/-25V. Adding something like a MAX232 would probably be a good idea.

Does it work with USB-serial interfaces? I don't think all(most?) of them implement handshaking.

They usually do implement handshaking, but the packetised nature of USB means that relative timings can get very screwed. 

[Mechatrommer]

IIRC the RS-232 spec is something like min. +/-3V and (absolute) max. +/-25V. Adding something like a MAX232 would probably be a good idea.
Does it work with USB-serial interfaces? I don't think all(most?) of them implement handshaking.

They usually do implement handshaking, but the packetised nature of USB means that relative timings can get very screwed. 

from my limited knowledge, the handshaking is done in chip level, not the chip's serial out pins. regarding timing, the detailed eeprom datasheet explanation can indicates if usb implementation is possible. and again from my limited knowledge, if its less than 64Bytes data at a time (62 actually), i think its possible, since i've done it with the ft232.