RM1101-USB-232 dongle questions

[adminy]

kidde_cc1101.ino was developed using a RM1101-USB-232 which unfortunately wasn't suitable in its stock form due to the SPI programming interface being fused off, and because the CC1101 isn't wired up to the ATmega48PA using hardware SPI pins (no idea why). So, I desoldered and replaced the ATmega48PA with an ATmega328P and added jumpers to connect the hardware SPI interface to the CC1101. Not pretty, but it works. Some pics of the before/after can be found here. Something like a SIGNALduino would be a better route to go, though they're relatively pricey.

You sure that cc1101 chip is disconnected? I think its just that there is an initialisation AT command which I believe connects the chip. surely the manufacturer isn't selling broken dongles?! right?!

Also just curious whats wrong with the AtMega 48 that's there? can you explain why replacement was needed?

[tofurky]

cc1101 isn't disconnected of course, and yes the dongles work from the factory. it wasn't being used in spi mode (hw interface on mcu, rather than bit banged) per the schematic, hence the need for jumper wires.

the atmega48 doesn't have much in the way of resources. i wasn't able to reprogram it in-circuit (could have been user error) and arrived at the conclusion the spi programming interface was fused off. i think my reasoning at the time was, if it requires removing it from the circuit for high-voltage programming, i might as well put a better chip back on instead.

atmega48: 4 KB ISP Flash memory, 256B EEPROM, 512B SRAM
atmega328: 32 KB ISP Flash memory with read-while-write capabilities, 1 KB EEPROM, 2 KB SRAM

[tofurky]

RM1101-USB-232_factory_2020-07-30.BIN.gz

i did manage to get a dump of the factory firmware, if you're interested. i think that means that i did get the SPI programming interface working after removing the chip (was 2020, memory is flakey) so it may have just been an issue with how i was trying to do it in-circuit.

[adminy]

I'm trying to use its transmitter as simple ook signal. just not sure what baud rate to set it to and how frequent to push data to the serial console, since I couldn't find anyone ever using this dongle as is for anything. Found https://github.com/minht57/TIVA_CC1101_UART but I think that's not working with the dongle. I'm gonna get a proper spectrum analyzer to be able to see if I can get it to work

[tofurky]

i didn't spend much time with factory firmware, but i think it's mostly hard-coded. iirc there was a utility, but there's so many permutations of register settings on the cc1101 that i think you'd be better off buying one of the "maker" oriented dongles like signalduino (https://wiki.in-circuit.de/index.php5?title=SIGNALduino_Stick). i don't know if they're still available.

i looked through some old files i had about the stick, i think this is the software; not many settings: