I want to close this out for posterity. I'm not a fan of TI's documentation, and their using of the 8 bit address (0xAA) is quite confusing. The bq28z610 uses standard 7 bit addressing with address of 0x55. The 8th bit is the Read/Write bit, which in my opinion, should not be linked in with the address. The real rub is the bq28z610 by default does not work with an sck of 400 KHz, which is the default speed of the Beaglebone, so the fix for this is to set a bit in the I2C Configuration register to enable 400 KHz operation -- which, of course, you must do via a host running at 100 KHz.
I suspect this will cause someone else frustration, so I post the solution here -- or, I might forget what I did in 6 months and need to come back and reference the solution! On Thursday, October 29, 2020 at 3:42:28 PM UTC-4 H. Nikolaus Schaller wrote: > It is much simpler than you think. Look into the bq chip technical > reference manual: > > the BQ28Z610 uses a series of 2-byte standard I2C commands with a 7-bit > device address of 0x55 (8 bits = 0xAA to write and 0xAB to read). > > You just have to know that Linux uses 7-bit addresses. > > I.e. use i2cget with 0x55. > Or use i2cdetect to find out on which address the chip is really > responding. > > > > Am 29.10.2020 um 20:33 schrieb Paul Beam <[email protected]>: > > > > Thanks. This part is totally confusing me. It is supposed to be an > "upgrade" of a part I have been using. I guess my time is better spent > getting the TI driver to work instead of accessing the registers directly, > which is what I had been doing. > > > > On Thu, Oct 29, 2020 at 3:08 PM Dennis Lee Bieber <[email protected]> > wrote: > > On Thu, 29 Oct 2020 10:23:39 -0700 (PDT), in > > gmane.comp.hardware.beagleboard.user Paul Beam > > <[email protected]> wrote: > > > > >Does the Beaglebone support 8 bit I2c addresses? I'm using a TI > bq28z610 > > > > Which Beaglebone? > > > > >which has I2C address 0xAA, but I cannot access it via i2ctools. I can > > > > Per the BBB TRM (TI SPRUH73P) > > """ > > 21.1.1 I2C Features > > The general features of the I2C controller are: > > • Compliant with Philips I2C specification version 2.1 > > • Supports standard mode (up to 100K bits/s) and fast mode (up to 400K > > bits/s). > > • Multimaster transmitter/slave receiver mode > > • Multimaster receiver/slave transmitter mode > > • Combined master transmit/receive and receive/transmit modes > > • 7-bit and 10-bit device addressing modes > > • Built-in 32-byte FIFO for buffered read or writes in each module > > • Programmable clock generation > > • Two DMA channels, one interrupt line > > """ > > > > BB-AI TRM > > """ > > The multimaster HS I2C controllers have the following features: > > • Compliant with Philips I2C specification version 2.1 > > • Supports a standard mode (up to 100 kbps) and fast mode (up to 400 > kbps) > > • Supports HS mode for transfer up to 3.4 Mbps (only for I2C3, I2C4 and > > I2C5) > > • 7-bit and 10-bit device addressing modes > > • General call > > • Start/Restart/Stop > > • Multimaster transmitter/slave receiver mode > > • Multimaster receiver/slave transmitter mode > > • Combined master transmit/receive and receive/transmit mode > > • Built-in FIFOs (16 bytes) for buffered read or write > > • Module enable/disable capability > > • Programmable multislave channel (responds to four separate addresses) > > """ > > > > vvv here is the important info > > > Per > > > https://www.totalphase.com/support/articles/200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing#8bit > > 8-bit addressing is not a proper I2C addressing mode. > > > > Your xAA is probably address x55 with read/write bit 0 (write) > > ^^^ here is the important info > > > > > > > > > -- > > Dennis L Bieber > > > > -- > > For more options, visit http://beagleboard.org/discuss > > --- > > You received this message because you are subscribed to the Google > Groups "BeagleBoard" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected]. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/o54mpf9itc7hbrl24v98h17cucfkvmjpn1%404ax.com > . > > > > -- > > For more options, visit http://beagleboard.org/discuss > > --- > > You received this message because you are subscribed to the Google > Groups "BeagleBoard" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected]. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CAA_M65N4%3DdHgSbVaOT%3D_Kfd7t_rr2PJNLjK2WNK8Jm6VnUfNnA%40mail.gmail.com > . > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a5021d4e-92aa-4ea2-b932-66acb691e196n%40googlegroups.com.
