[Tinyos-help] Connecting PCF8563 RTC to Iris

[Janos Sallai]

Andres,

> I have read that I2CPacket.write(adr, len, data) returns always success.

This is not true. Here's an excerpt from
tos\chips\atm128\i2c\Atm128I2CMasterPacketP.nc:

179  async command error_t I2CPacket.write(i2c_flags_t flags, uint16_t
addr, uint8_t len, uint8_t* data) {
180    atomic {
181      if (state == I2C_IDLE) {
182	state = I2C_BUSY;
183      }
184      else if (state == I2C_OFF) {
185	return EOFF;
186      }
187      else {
188	return EBUSY;
189      }
        ...

That is, your consecutive calls to I2CPacket.write will fail without
waiting for I2CPacket.writeDone in between.

Janos


On Thu, Jul 30, 2009 at 7:31 AM, Andres Vahter<andres.vahter at gmail.com> wrote:
>
> On 29.07.2009, at 18:31, Janos Sallai wrote:
>
> Andres,
>
> I2CPacket.read and I2CPacket.write are split phase operations. You
> have to wait for the corresponding readDone or writeDone events before
> issuing the next read or write, otherwise the subsequent operations
> may fail.
>
> Janos
>
>
> Hi,
> I have read that I2CPacket.write(adr, len, data) returns always success.
> There is patch for
> that: http://mail.millennium.berkeley.edu/pipermail/tinyos-devel/2009-July/003977.html
> I tried it with copy-paste method (don't know how to apply it correctly).
> And I'm still getting SUCCESS when I'm tryng to write to non existing I2C
> device - I should get EINVAL with that patch - am I right?.
> ---------------------------------------------------------
> buffer[0] = 0x00;
> buffer[1] = 0x00;
> buffer[2] = 0xF;
> buffer[3] = 0x00;
>
> if (call I2CPacket.write(I2C_START, 0x41, 1, buffer) == SUCCESS) {
> call Leds.led2On();
> }
> ---------------------------------------------------------
> It returns always success. I don't have device with address 0x41 connected.
>
> What about external pulldown, why is it changed
> from
> if (hasExternalPulldown)
> to
> if (!hasExternalPulldown)
>
> How is addressing managed? If I have a device with 8 bit address 0xA2 should
> I use that address in I2CPacket.write or should I use 7 bit address 0xA2 >>
> 1?
> And last question: if I have device with I2C address 0xA2 and I want to
> change register 0x02 value in that device to 0x0F - how should I do that, is
> following code right?
> buffer[0] = 0x02; // reg addr
> buffer[1] = 0x0F; // value
>
> if (call I2CPacket.write(I2C_START, 0xA2, 2, buffer) == SUCCESS) {
> }
>
> Andres Vahter
>
>