Messages

Can I erase the full chip through ISP this way?

A full device erase operating is always fail to me Now.Is there anyway to erase the full device but software handshake chip?

A full device erase should clear the security bits.but if you consure this chip is still useful to me?Is this chip still can download codes?

You mean that I cant't read chip's Identity number or BOOT VECTOR or STATUS BYTE's value?

I mean that just cant't read chip's Identity number or BOOT VECTOR or STATUS BYTE's value? if I set security bit

 OK,if I  set  security bit1 or set security bit2 or set security bit3(May be set all three security bit )when download my code to P89C662HBA,Does it will cause I can't  Handshake to MCU successuflly next time？Who can help me？

OK，who can tell me set security bit1、 set security bit2 and set security bit3 meaning，if I choose any one when programming code，what will happen to MCU;

Is there anyone who has used P89C662HBA？Please teld me your way of programming code by serial port or parallel tool.Thank very much.

May be bad chip Serial debugging assistant software Screen On,the last picture upload failed. The picture is stable data which is not "U"

May be bad chip waveforms

Good chip Serial debugging assistant software Screen

because flash magic software so quickly that I can't capture waveforms in time ,so I use Serial debugging assistant software Send "U" persistent. The good chip will Reply "U". Good chip waveforms

Debugging environment

Schematic

OK I'm sorry for that behavior,Both Txd and Rxd pin will light corresponding LED if there have data.When I want to reload my codes(PSEN Low,EA/P26/P27 High),Microcontrollers sometimes run my previous code to send stable data(such as "test program") through Txd pin and sometimes do nothing for a while and then run my previous code to send stable data through Txd pin  .But Rxd pin everytimes have data.And everytime fail to reload my codes.