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Interfacing with the voice chip
I figured out how to interface with the voice chip. Its very easy. In the process, I also found out a good way of experimenting with the MCU in place. I cut the Vdd traces going into the MCU and added jumper wires instead (there are two vdd lines going into the MCU with the trace exposed). This allows me to turn off the cpu whenever I want to send my own signals, and turn on the cpu whenever I want to see what the cpu is doing. I also soldered very thin wires (I used a single strand from a multi strand wire) on the the legs of the MCU so I can attach the probes and sniff the logic data or replay the data.
So here is how to interface with the voice chip.
Voice chip is SPI.
To send voice commands
CLK period is about 1ms
CLK Goes high for about 6 clock periods
8 bits of data are shifted with the clock (MSB first)
Each 8 bit number represet a voice stored in the chip
Some example speeches (I did not try all 256 locations, just a few).
Binery Hex Speech
10000101 85 Channel Mode
10000001 81 Tx Memory
10011001 99 Menu
01100000 60 0
01100001 61 1
01100010 62 2
01100011 63 3
00100000 20 Chinese ???
00100001 21 Chinese ???
00100011 22 Chinese ???
Here is a video of the MSO19 sending data into the voice chip (I removed the dummy load, since my TX is completely off).