Thank you! That helped me get up and running. There were two things I was missing. First, the call to gpio_set_output_options() with GPIO_OTYPE_OD appears to be critical; it's not sufficient to put this in gpio_mode_setup(). Second, with GPIO_OTYPE_OD, apparently I need to use i2c_set_speed(), instead of i2c_set_clock_frequency() and/or i2c_set_fast/standard_mode().
After that, my address write received ACK. But I still was not able to use i2c_send_data(); this apparently did nothing. However, using i2c_transfer7() as you suggested, worked fine. So I am good for now (albeit a little confused about the old/low-level interface versus the new one..). Would it be helpful for me to submit a working L1 I2C example for libopencm3-examples <https://github.com/libopencm3/libopencm3-examples>? _chris On Sun, Aug 2, 2020 at 10:24 AM Karl Palsson <ka...@tweak.net.au> wrote: > > https://github.com/karlp/libopencm3-tests/tree/master/tests/i2c-master > is the code I wrote while developing the "standard" api. (You > shouldn't really have to know about the v1/v2 differences, for > the most part...) Those "set_fast_mode" and "set_standard_mode" > are part of the original very low level apis. you (probably) want > something more like: > > > https://github.com/karlp/libopencm3-tests/blob/master/tests/i2c-master/i2c-master.c#L29-L38 > (i2c_set_speed( > <https://github.com/karlp/libopencm3-tests/blob/master/tests/i2c-master/i2c-master.c#L29-L38(i2c_set_speed(>) > and then just i2c_transfer7() > > The main-<hardware> have the onnly board specfic setup required, > normally setting up clocks and gpio modes. > > There's a couple of issues reported with i2c as well: > https://github.com/libopencm3/libopencm3/pulls?q=is%3Apr+is%3Aopen+i2c > that _may_ be relevant to you, or at least to bear in mind. > > > Chris Chronopoulos <chronopoulos.ch...@gmail.com> wrote: > > Hmm, well update - I figured out that I was missing the > > following line: > > > > rcc_periph_clock_enable(RCC_GPIOB); > > > > before my GPIO setup calls. Makes sense. The thing I'm confused > > about now is the clock speed. With i2c_set_fast_mode(), I get a > > clock speed of 178 kHz. With i2c_set_standard_mode(), it's 266 > > kHz. Weird, shouldn't fast mode be.. faster? > > > > Also, one more thing: if I try and wait for "address > > transferred" by doing: > > > > while (!(I2C_SR1(I2C1) & I2C_SR1_ADDR)); > > > > after the i2c_send_7bit_address() call, then it gets stuck > > here. So I think I am still doing something wrong with the > > setup. > > > > > > On Sat, Aug 1, 2020 at 6:00 PM Chris Chronopoulos < > > chronopoulos.ch...@gmail.com> wrote: > > > > > I've also noticed that if I put in the while-loops to check for status > > > register updates, e.g. > > > > > > while (!((I2C_SR1(I2C1) & I2C_SR1_SB) > > > & (I2C_SR2(I2C1) & (I2C_SR2_MSL | I2C_SR2_BUSY)))); > > > > > > Then this just gets stuck, confirming that the start condition is not > > > being sent. > > > > > > On Sat, Aug 1, 2020 at 5:52 PM Chris Chronopoulos < > > > chronopoulos.ch...@gmail.com> wrote: > > > > > >> Hi, just joined this list, not sure what the protocol is.. but I have > a > > >> question about getting I2C working on the STM32L1(52RE). > > >> > > >> First of all, I see that there are two versions of the I2C API: v1 and > > >> v2. Can someone explain what the difference is between these? From > digging > > >> through the library, I can see that different device families use > different > > >> versions, e.g.: > > >> > > >> F0: v2 > > >> F1: v1 > > >> F2: v1 > > >> F3: v2 > > >> F4: v1 > > >> F7: v2 > > >> L0: v2 > > >> L1: v1 > > >> L4: v2 > > >> > > >> So when following code examples, I guess I need to find examples that > use > > >> the v1 API. In libopencm3-examples, the only STM32 I2C v1 example I > could > > >> find is this one for F1 > > >> < > https://github.com/libopencm3/libopencm3-examples/tree/master/examples/stm32/f1/other/i2c_stts75_sensor > >. > > >> Unfortunately, the i2c_setup() function in this code doesn't compile > for > > >> L1, because of some differences between the RCC and GPIO API's > (namely, > > >> RCC_AFIO and gpio_set_mode() are not defined for L1). So I made some > > >> adjustments based on my best guesses, and ended up with this code > > >> < > https://gist.github.com/chronopoulos/d34de9b6119d4ec052451d6afaa99e79>, > > >> which compiles. But, when I monitor the I2C lines with a logic > analyzer, I > > >> see nothing. Dead silence. > > >> > > >> Am I missing something? Can anyone provide an example of I2C being > used > > >> on STM32L1? > > >> > > >> > > _______________________________________________ > > libopencm3-devel mailing list > > libopencm3-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/libopencm3-devel
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