Data on 16034984

[Ludis Langens]

Andy Whittaker - Chester UK wrote:
> 
> However, does anyone have details on any of the chips, particulally the Fuel
> Modelling Device (U13 and U15) number 16034984? These are I2C addressed
> devices therefore I'm after register and port information.

It is an SPI device, not an I2C device.

Output byte:
 bit7: Input source select; 0 == inputs, 1 == status
 bit6: IRQ enable (IRQ on falling edge of ESTHi)
 bit5: ??
 bit4: Pin 8 source; 0 == pin 9 input, 1 == bit3
 bit3: Pin 8 output data when bit4 is set
 bit2: EST enable
 bit1: Limp home watchdog bit
 bit0: CTS pullup; 0 == 4K ohm, 1 == 348 ohm

Input byte:
 bit7: Pin 41 input
 bit6: Pin 40 input
 bit5: Pin 39 input
 bit4: Pin 38 input
 bit3: Pin 37 input
 bit2: Pin 36 input
 bit1: Pin 35 input
 bit0: Pin 34 input

Status byte:
 bit7: ??
 bit6: Pin 52 input (from injector output)
 bit5: ??
 bit4: 0 == 6 or 8 cylinder
 bit3: 0 == 4 or 8 cylinder
 bit2: ??
 bit1: ??
 bit0: ??


Once this chip asserts it's IRQ output, the only way to deassert it is
to write a zero to the IRQ enable bit.

The watchdog bit needs to be written with alternating values faster than
a certain rate, otherwise the limphome mode is forced.

The high bit of the output byte chooses between response bytes
(input/status) for that very SPI transfer.

Esoteric data:  The chip select must be dropped and asserted for each
SPI transfer.  If it isn't, then subsequent SPI transfers simply rotate
through an internal shift register.  The internal register is only 7
bits long - the first SPI bit doesn't use the shifter.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/

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