Guide to EPROMs

Guide to
EPROM sizes and Hexadecimal numbers

Most EPROM programmers use hexadecimal numbers to configure start and end addresses etc. For non computer programmers this can be a bit confusing. This guide is intended to simplify things.
Hexadecimal is base 16 arithmetic. That is it uses the numbers 0 to 9 then the letters A to F before it increments the next higher column. So for example 7FFF is one less than 8000.


EPROM Type	Size - bits	Size - bytes	Length (hex)	Last address (hex)
2716	16Kbits	2KBytes	800	007FF
2732	32Kbits	4KBytes	1000	00FFF
2764	64Kbits	8KBytes	2000	01FFF
27128	128Kbits	16KBytes	4000	03FFF
27256	256Kbits	32KBytes	8000	07FFF
27512	512Kbits	64KBytes	10000	0FFFF
27C010, 27C100 etc	1Mbit	128KBytes	20000	1FFFF
27C020	2Mbit	256KBytes	40000	3FFFF
27C040	4Mbit	512KBytes	80000	7FFFF

Notes:
Only some of the part numbers for each size of EPROM are listed. If you have a 2Mbit EPROM other than a 27C020, for example, you can use the same numbers as for the 27C020. Also EPROMS with a 'C' in the middle of the number (meaning CMOS) are the same sizes as the same number without the 'C'. eg 27C256 is the same as 27256 etc.
On the Dataman S4 programmer, if you select a particular EPROM type (using PROM or FUNC/PROM) then select BURN, the S4 will default to the full range of addresses for the device type selected. ie Select a 27C256 and it will display 00000-07FFF. (Press ESC to get out of the BURN function)
When using Binary transfer mode on the S4, it remembers the start and end address of the last file transfer. If you change EPROM types it is going to be necessary to type in the correct start (usually 00000) and end address for the new EPROM type (using the Last Address column above) when you start your next binary transfer.