I am looking to sniff a couple of lines off a Serial ISP Programmer. The serial programmer target device is an OKI - L66Q592 16-bit microcontroller. I have looked nearly all over the internet and exhausted all of my resources to get the programming protocol for this device and couldn’t find anything. So here I am trying to use a off the shelf hardware sniffer to capture the serial information as it programs the device. The serial information will have to be decoded and written back to the hardware device. Developer will choose an analyzer that their familiar with and has the ability to log, analyze and write back over the serial network.
Attached is a datasheet named L66 Serial.PDF. In section 2.4 it explains how the serial mode programming is accomplished using an YDC programmer which they do not sell anymore. The datasheet also shows the pins that are used for serial mode. This section is exactly how the current programmer is completing the programming operation now.
There are certain states the OKI processor must be in order for it to the accept changes written over the serial network. There will be a small hardware development that will take place to pull the TEST pin to high voltage. The EA pin is the input to set serial mode, it should be connected to Vdd. I took some time with a continuity meter and beeped the serial programmer PCB. I attached a schematic Image of how the serial programmer PCB is laid out and how it’s connected to the OKI processor.
The Pins to access the Flash memory:
Pin 95 - P11_2 FLACLK (Serial clock input)
Pin 93 - P11_0 FLADAT (Serial data I/O)
Pin 92 - TEST FLAMOD (High voltage input for serial mode setting)
Pin 3 - EA Input for serial mode setting
1st step I will purchase a logic analyzer recommended by the developer which he or she is familiar with. The analyzer will be used to see what’s going on with the 4 pins. Create a hardware interface to mimic the states of the pins
2nd step I will purchase an off the shelf serial analyzer which will capture the data and determine the baud rate. The analyzer must have the ability to write back over the serial network.
3rd step will be to decode the data get the writing protocol and reading protocol documented.
4th step Create a Basic GUI that has 4 functions. Open serial Hex file, Save Serial Hex file, Write and Read.
Please note the step above is just a small flow of how the job might follow. The developer may have another method. Also the hardware above could be the most basic. USB to Serial would be a method of my choice. If I have to assembly anything parts should be through-hole.
Developer Knowledge: C++, C, Serial, USB, Decoding Serial, Electrical Engineer
You can download the files here [url removed, login to view]