| ??? 11/16/07 14:18 Read: times |
#147071 - P89C51RD2 and external RAM |
Hello,
I'm using a NXP P89C51RD2 with external 32KB SRAM (CY62256LL-70) connected to the MCU through a 74AHC573. The CE\ RAM's pin is connected to A15 The OE\ RAM's pin is connected to READ\ The WE\ RAM's pin is connected to WRITE\ (PSEN is not used and EA/VPP is pulled up with 10kohms resistor) Here is my problem : I made 12 identical boards, 2 of them doesn't work, the others work well. The program in the internal Flash seems to stop only when I use the RAM data above 0x9C addresses. Please, can someone help me to understand what is the reason of the bug ? Thank you very much for your answers. |
| Topic | Author | Date |
| P89C51RD2 and external RAM | 01/01/70 00:00 | |
| -70?? | 01/01/70 00:00 | |
| Can you post any example code here? | 01/01/70 00:00 | |
Board quality | 01/01/70 00:00 |