Hi,
on bread board using MAX232 and using serial connections pin 2,3 & 5 t communicate with my hardware but this is not responding, is it the case that we can not use the controller on bread board? or something else?
1) Check the clock ? Is it alive and is it of correct value ? (Check with the corresponding specification ) Minimum and maximum high and low times specified in the data sheet must be observed. 2) Chcek the powersupply and GND. Also the capacitorss. If you use capacitors on your own, then those 2 capacitors should be of correct value to generate the desired clock. Mostly, capacitors are the main culprits while bringing up a board with a processor/controller. 3) Check the capacitors with the MAX232 also. All 4 capacitor values should be of correct value. 4) RxD, TxD lines carry the data which correspond to 2 and 3 respectively. So, try loopback test as below - On the cable, short lines 2 and 3. This connects the Transfer line coming out of the processor to the Receive line going in.
Karthik Balaguru
You have to put the P89C51RD2 in to program mode.
You need to read the ISP (In System Programming notes on the NXP web site or Flash Magic web site).
The concept involves /PSEN being low while releasing from a Power On Reset (POR) or Normal Reset....... only then will the P89C51 go in to programming mode.
Joe
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.