Microcode Bootloader without MAX232

Hi all,

It is so exciting that we can program the chip without using the real programmer.

Previously, i was using my old pc with parallel port and epic programmer to program the pic. But since I have change my new laptop, there is no serial or parallel port on it.

My questions are

1. if I use the bootloader method to program the PIC, I must have a serial port?

2. how about if i use the usb to serial converter?

3. with the usb to serial converter, can i by pass the MAX chip? This is because the voltage level for the serial port will be 0 and 5v only.

Looking for your help. Thanks!

If you use a USB to Serial adapter you will still need a MAX232 as the adapter will output RS232 levels but there are other converters available that output TTL levels suitable for direct connection to a PIC.

Based on the FTDI chips.....

http://apple.clickandbuild.com/cnb/s...es%3A+TTL-232R

http://apple.clickandbuild.com/cnb/s...0&title=MM232R

This one uses a different chip and I currently use these to program AND Power my PIC projects

http://www.dontronics-shop.com/produ...1&cat=0&page=1

with the MicroUSB you will need a 1K resistor in RX and TX if your PIC is running on 5V as the device itself operates at 3.3V logic levels

You can even replace the MAX232 IC by Transistor or else inverter circuit.

Thanks for both of you of the reply.


By the way, do I need to setup all the configuration such as the ADC, comparator in the bootloader file? Or when setup it up in the program code?

Please help.

Thanks

You don't have to set anything else than config fuses... wich often are correctly set.

Hi

When using the Microcode loader, I found that on my laptop I have to hit reset and then click away the waiting for reset box to see the reset message, yet on my desktop it is okay.

I use a USB-Serial link on the laptop the the built in serial port of desktop and there does seem to be a slight difference when using the software.

So worth being aware of.

If you follow this link it will explain more showing method1 and method2.

http://www.cncdudez.com/Firmware.html

Regards

Sean.

Thanks!

The only thing if using usb to serial converter, most probably we need to use the hard reset button to pull the MLCR to Gnd. Is the above statement true?

If the loader file that I have only provided in 4Mhz and 20 Mhz, but i want to have the INTRC Clock Out as the clock system, what should I do? It is possible to modify the hex value in the bootloader file according to the configuration hex location?

Sorry! so many question here.

Thank very much.