tabemann
commented
1 week ago On Wed, Sep 4, 2024 at 10:34 AM 592969 @.***> wrote:
Having a lot of fun playing around with zeptoforth but I am stuck on this issue.
I have looked at the I2C examples in the "test" folder but it is not clear how to read or write a register on a device. What I am trying to do is set a RP2040 up as the master and read and write registers from a slave device. Here is my init code to set it up and this works.
16 constant recv-buffer-size recv-buffer-size buffer: recv-buffer i2c import 0 master-i2c 0 7-bit-i2c-addr $1F 0 i2c-target-addr! 0 enable-i2c 0 0 i2c-pin 0 1 i2c-pin
I know I need to use ">spi" and "spi>" but it is not clear how to send the address to read or write and how it will be returned.
SPI and SPI> are for interacting with SPI devices, not I2C devices, I should note.
About reading and writing register addresses on I2C peripherals, that is a matter of how the I2C peripheral works, not the I2C peripheral; zeptoforth itself does not know about this.
However, in the common case you are probably looking at something like this:
For writing,
my-subaddr-reg-buffer my-subaddr-len my-i2c-peripheral >i2c-restart drop my-data-buffer my-data-len my-i2c-peripheral >i2c-stop drop
These two steps can be combined if you write the subaddress and the data to write into a single buffer and send that with >i2c-restart-stop .
For reading,
my-subaddr-reg-buffer my-subaddr-len my-i2c-peripheral >i2c-restart drop my-data-buffer my-data-len my-i2c-peripheral i2c-restart-stop> { my-real-data-len }
In your case my-data-buffer would be recv-buffer and my-data-len would be 16.
Hope this helps,
Travis
592969
Having a lot of fun playing around with zeptoforth but I am stuck on this issue.
I have looked at the I2C examples in the "test" folder but it is not clear how to read or write a register on a device. What I am trying to do is set a RP2040 up as the master and read and write registers from a slave device. Here is my init code to set it up and this works.
I know I need to use ">spi" and "spi>" but it is not clear how to send the address to read or write and how it will be returned.