does the speakjet synth work on stm32F4?

4 posts in this topic

Hi All, I've got an stm32F4 and a speakjet chip knocking around, so I thought I'd try out the speakjet synth for mios32 in




Unfortunately, the schematic in the svn repo for the app. is for the lpc core module,  looking at the schematic compared to the lpc module pinout, if I've got this right, the speakjet chip connects d2,m0,m1,rst to J10.d3, .d2, d1 and .d0 and the speakjet rcx pin connects to J5b.A7, will the midibox_sj2_v2 app. work if I connect the respective pins as they're laid out on an stm32F4 (pe8,9,10,11 for the J10 pins and pb1 for the j5b.a7-rcx connection)?

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in the meantime I thought I'd try compiling the app. to see whether my toolchain is setup correctly (looks like it, I get errors when compiling \o/) and I've answered my own question, as the app. currently stands in the repo, it won't just work, giving me this error message:

this MIOS32_BOARD hasn't been prepared yet!


Looking in the mios32_config.h file I see this #if:

// Dedicated SpeakJet pin assignments
#if defined(MIOS32_BOARD_MBHP_CORE_STM32)
# error "TODO!"
#elif defined(MIOS32_BOARD_MBHP_CORE_LPC17) || defined(MIOS32_BOARD_LPCXPRESSO)
# define SPEAKJET_PIN_RST_N  2

# define SPEAKJET_PORT_M1    2
# define SPEAKJET_PIN_M1     3

# define SPEAKJET_PORT_M0    2
# define SPEAKJET_PIN_M0     4

# define SPEAKJET_PORT_D2    2
# define SPEAKJET_PIN_D2     5
# error "this MIOS32_BOARD hasn't been prepared yet!"

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When you search for SPEAKJET_PORT in the source files, you will find the places which need to be adapted.


Direct port access is a very dirty method (actually it was a bad idea to release the app this way...)


Currently I'm not able to test this by myself, but it could make sense to access the module via J5 IOs instead.

A tutorial can be found under:


Best Regards, Thorsten.

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Sorry to dredge this thread up from the mists of ancient time, but.. I'm considering making up a little PCB for the LPC17-based implementation of Audiocommander's MB SpeakJet synth, based on the schematic in the SVN. Would you recommend I try and rejig the circuit to use a different set of IO pins? It currently uses pins P2.2-2.5 (PWM1.3-1.6).

Would changing the pins used (if that's necessary) require a major rewrite of the MIOS software?

I'd also like to add an amp section (with volume attenuator) to bring output level up to Eurorack synth levels.


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