Problems connecting the uM-FPU64 28-pin breakout board to the Propeller C3
youngdave
Posts: 70
FPU64_SPI_Demo.spin reaches software reset of the uM-FPU64, and then stops because it cannot get the sync byte.
Any tips would be very much appreciated.
* Objects used
FPU64_SPI_Demo.spin (modified by me for Propeller C3)
│
├──Parallax Serial Terminal.spin
│
└──FPU64_SPI_Driver.spin
* Connections
uM-FPU64 Propeller C3
3.3V 3.3V
GND GND
SCK SCLK
SOUT/SDA
SIN/SCL PSDA
/SS SS6
MCL P0
Any tips would be very much appreciated.
* Objects used
FPU64_SPI_Demo.spin (modified by me for Propeller C3)
│
├──Parallax Serial Terminal.spin
│
└──FPU64_SPI_Driver.spin
* Connections
uM-FPU64 Propeller C3
3.3V 3.3V
GND GND
SCK SCLK
SOUT/SDA
SIN/SCL PSDA
/SS SS6
MCL P0
Comments
Brian, thanks for your reply.
this is the breakout board.
http://micromegacorp.com/products.html
TIA David Young
For Two-Wire SPI (which the demo is coded) you must connect SIN to SOUT via a 1K resistor (Brown, Black, Red) . SOUT is connected only to the 1K resistor. SIN is connected to the 1K resistor and to the C3. Whatever pin on C3 to which SIN is connected, that pin number is used in the SPI call for _both_ data-in and data-out.
While this would work for most Propeller boards, with the C3 you also need to pulse the counter chip to select the appropriate chip select line. The C3 uses a cool trick to save on I/O pins. You'll need to take a look at the C3 documentation to take advantage of this trick.
The other alternative is to use some unused I/O pin (I don't know how many there are off hand) to control the chip select line of the uM FPU64 chip.
I must have a software problem.
How do I attach object files to replies?
The connections between the FPU64 and the C3 are as you describe.
I must have a software problem.
Ive attached the objects c3_uM-FPU64_demo_0 (modified for use with the FPU64) and FPU64_SPI_Driver (unmodified).
Can anyone see the problem here?