FMC150 User Manual
r1.6
FMC150 User Manual
January 2012
www.4dsp.com
- 15 -
5.4 Guidelines for controlling onboard monitoring
The FMC150 holds an AMC7823 for monitoring several power supply voltages on the board
as well as temperature. The device can be programmed and read out through a SPI bus.
1) The measured values must be multiplied by one or two to get the actual level. The
measured value on channel 4 must be multiplied by 5.7 to get the actual level
2) Continuously operating the SPI bus might interfere with the A/D or D/A conversion
process resulting in signal distortion. It is recommended to program the minimum and
maximum thresholds in the monitoring devices and only read from the devices when
the interrupt line is asserted (MON_N_INT). Only the first four channels can be
monitored with thresholds. These are the main supplies derived from the other voltages
on channel 4 to 7.
3) It is recommended to power down the unused features; DAC operation, precision
current source, and reference buffer amplifier.
4) Internal reference must be selected. Since the AMC7823 is powered from 3.3V only
internal reference of +1.25V is allowed.
5) Only internal trigger mode is supported. Auto mode is recommended to continuously
monitor channel 0 to channel 3 and verify against the programmed thresholds.
Parameter:
Voltage
Formula
Channel 0
3.3V Analog
2.0 * ADC0
Channel 1
3.3V Clock
2.0 * ADC1
Channel 2
1.8V Analog
1.0 * ADC2
Channel 3
1.8V Digital
1.0 * ADC3
Channel 4
12V
5.7 * ADC4
Channel 5
3.3V
2.0 * ADC5
Channel 6
VADJ
2.0 * ADC6
Channel 7
3.8V
2.0 * ADC7
Temperature (ch.8)
Table 6: Temperature and voltage parameters
5.5 Controlling onboard FANs
The FMC150 holds two power headers which may optionally be used to power low profile
FANs glued on the devices. On the FMC150 each FAN can be switched off individually by
pulling its control signal high. The control signals are connected to the GPIO on the AMC7823.
6 Environment
6.1 Temperature
Operating temperature
