> On Fri, Oct 3, 2008 at 4:34 AM, Harold Hallikainen > wrote: >> I'm looking at using an M25P32 in a PIC project. The data in this chip >> will be unchanging, so I don't want to have to write code to program it >> through the PIC. Instead, I'm thinking of an in-circuit SPI programmer >> that could program the chip before the PIC is programmed (and all lines >> are tri-state). Does anyone have a favorite device for this sort of >> application? It seems like it should be something that sits on the end >> of >> a USB cable and connects to the SPI lines and maybe Vpp. > > Not so sure if this helps. > http://www.xilinx.com/support/documentation/application_notes/xapp974.pdf > > Xiaofan Thanks! But, you're right... It's not much help. It is quite similar to something else I've been working on this week where we program an Altera serial configuration device from the FPGA JTAG port by loading a special configuration in the FPGA that provides the path to the config device. Here, though, I have a Unicode bit map I want to put in an SPI flash since it will not fit in the PIC flash. I could program it before it's put on the board, but I'd like the ability to program it in-circuit without having to route the program data through the PIC. When the PIC is blank, all the I/O pins are tri-stated, so it seems that I should be able to hang a programmer on those SPI lines and program the chip. Although the chip can be programmed without elevating the voltage on Vpp, a programmer might want to do that. I think a pull-up to Vcc would allow an external programmer to pull it high, if needed. So... it seems there otta be a little USB device that has MISO, MOSI, SpiClk, CSn, and maybe Vpp that I could hook on the chip in circuit and program it. It really seems to be a software problem (it should be pretty easy to bit bang these lines). Thanks for the comments! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist