[Tinyos-help] Problems using Flash lines

[David González]

Hi,
I´m working with mica2 motes and my own sensorboard that includes a 
16bit-ADC.In order to comunicate the ADC and the mote I use the 
following lines: FLASH_SO, FLASH_SI and FLASH_CLK conected to ADC_DOUT, 
ADC_DIN and ADC_DCLK repectively, on the same way as other sensorboards 
as micawb with Melexis and Intersema sensors.
My problem is with the FLASH_SO line. I have 0,9*Vcc in this line if the 
sensorboard is not attached, and a fixed voltage of 0,5 V if it is. I 
use similar routines to write and read data from ADC that micawb driver 
uses. The bytecontrol writting is OK but ADC_DOUT is always fixed to 
0,5V. There are a switch (adg715) between ADC and mote.

StdControl.start {
TOSH_MAKE_FLASH_IN_INPUT();
TOSH_MAKE_FLASH_OUT_OUTPUT();
TOSH_MAKE_FLASH_CLK_OUTPUT();
TOSH_CLR_FLASH_IN_PIN(); //but the line have a voltage near Vcc
state = IDLE;
}

void ctrlbyte_write(char word) {
//... similar write_bit() in micawb driver
}
   
uint16_t adc_read() {
//... similar adc_read() in the same file
}

Has anyone any idea to help me?
Thanks in advance,
Regards.