| ??? 07/16/09 10:09 Read: times |
#167403 - Follow the Standards Responding to: ???'s previous message |
The RS232 connector DB9 either male/female is standard for UART RS232C.
The pins 1 through 9 and chassis are defined what kind of signal can carry, the voltages, etc, this is a standard. Don't change that. If the MAX232 or equivalent is on different board how it is powered ? Is the Signal Ground properly connected betwen PC - MAX232board - HMIboard ? Is the Frame Ground properly connected betwen PC - MAX232board - HMIboard ? Don't mix the standards with personal preferences. If the ISP is optional then the connector should be something else like a 4 or 6 or 10 pin header or even an RJ11 jack or maybe an RJ45 jack on the HMI board. Can you provide the schematic for the MAX232 board ? The RST line on P89V51RD2 is already controlled by the supervisor chip. You may need a circuit to control either manual or auto by other means the RST input for the microcontroller. Anyway the NXP recommendations is that this is not needed. The MAX813 supervisor chip assert the RST line for 150ms after the power on is stabilized. From this point there are 400ms that the boot system on P89V51RD2 is trying to check for ISP action. This is the time window that the programmer and the flashmagic tool should respond to start the ISP procedure. K.L.Angelis |
| Topic | Author | Date |
| Need help with ISP of P89V51RD2BN | 01/01/70 00:00 | |
| P89V51RD2 HMI boad Schematic ? | 01/01/70 00:00 | |
| Link to HMI board schematic | 01/01/70 00:00 | |
| You schematic will not work for the P89V | 01/01/70 00:00 | |
| ISP of NXP chips | 01/01/70 00:00 | |
| We read a lot of discussion first | 01/01/70 00:00 | |
| Seems to be OK | 01/01/70 00:00 | |
| where is the MAX232 ????? | 01/01/70 00:00 | |
| The MAX232 is on a different board | 01/01/70 00:00 | |
| More things we will try | 01/01/70 00:00 | |
Follow the Standards | 01/01/70 00:00 |