hallo,
I try to made my own ISP programmer to download data into AT89S52.
I already done for read signature, writing to flash, read to flash.
But I can not erase to the chip AT89S52. Why?
For erasing the chip I already send the erase instruction (1st byte:10101100b 2nd byte:10000000b 3rd byte:00000000b 4th byte:00000000b) to chip, but data not change to FFh.
Is it any special timing to erase the chip?
Please give me some information about chips erasing (AT89S52).
thankyou verymuch.

hen.