Post by thread:PLEASE - HELP ME! PIC17C4X

Hi, Did you run someone external program on PIC17C4X, where's the executable code is into the a external RAM? I wrote a program into the external EPROM (address 0x0000) of PIC17C4X that loads a .bin file from serial, and put it on external RAM. My program verify the program on RAM is correct with success, but, when try to execute it, fail!. I think that then RAM -100 -120ns that i'm using are too slow for PIC17C4X. Am i correct? Miguel.

Miguel: Try a slower XTAL clock frequency to verify your conclusion ! regards, Graham Daniel WF AUTOMACAO wrote: {Quote hidden}> > Hi, > > Did you run someone external program on PIC17C4X, where's the > executable code is into the a external RAM? > > I wrote a program into the external EPROM (address 0x0000) of > PIC17C4X that loads a .bin file from serial, and put it on external RAM. > My program verify the program on RAM is correct with success, but, > when try to execute it, fail!. > I think that then RAM -100 -120ns that i'm using are too slow for > PIC17C4X. > > Am i correct? > > Miguel.

>PIC17C4X that loads a .bin file from serial, and put it on external RAM. Miguel, I hope your program is executing from a different part of memory. The PIC17 chips can program themselves using the table write commands. You need to have the external ram at a different address during this operation for it to work properly. Otherwise, you may be programming the internal ROM. Just because Vpp is 5v doesn't mean it won't try to program - it just won't program reliably! > I think that then RAM -100 -120ns that i'm using are too slow for >PIC17C4X. Microchip recommends 100nS chips for 20MHz part. If you look at the timing diagrams, they are 2 clock times wide. Andy ================================================================== Andy Kunz - Montana Design Go fast, turn right, and keep the wet side down! ==================================================================