HiRel/CanSat/Slave Sensors

Type	CanSat Slave Sensor	Schematic	Description
V1.0	200px|CanSat Slave Sensor V1.0	CanSat Slave Sensor v1.0 Schematic PDF

Sensors

The sensors board comprises:

• a HIH-5030-001S humidity sensor
• a TC1046VNBTR temperature sensor
• a MPXH6115A6U pressure sensor

Mixed-Signal I/O

The analog inputs are digitized with the help of a 20-Port Programmable Mixed-Signal I/O MAX11300. The board pinout is compatible with the one of the MAX11300 evaluation board.

Connections

The MAX11300 I/O ports connections are provided in the following table:

Port	Signal	dir
0	3.3 V	in
1	5 V	in
3	humidity	in
5	temperatire	in
7	pressure	in
9	LED 0	out
11	LED 1	out
13	LED 2	out
15	button 0	in
17	button 1	in
19	button 2	in

The buttons close a circuit to the ground. The other 9 ports are routed to connector J2.

The digital power supply is 3.3 V. the analog supply is 5 V.

Communication

The basic SPI frame uses 24 bits:

• 7 address bits
• 1 read/write bit
• 16 data bits

The chip supports a burt mode where the basic frame can be enlarged by multiples of 16 bits.

Configuration

There is one configuration register for each of the 19 I/O port. The configuration registers are found at addresses 20_h to 33_h. They are complemented by a DAC value each, at addresses 60_h to 73_h. These DAC values can be used to set the logic levels.

The 4 configuration register MSBs define the functionality of the port. Here some possible values:

• 0 : high impedance
• 1 : Digital input with programmable threshold
• 3 : digital output with DAC-controlled level
• 7: analog input to single-ended ADC

The configuration register LSBs provide parameters.

ADCs

ADC ports, registers 20_h, 21_h, 23_h, 25_h and 27_h, are configured with value 7100h.

Digital outputs

Digital output ports, registers 29_h, 2B_h and 2D_h, are configured with value 3000h.

The output level is set by a DAC: for 3.3 V, registers 69_h, 6B_h and 6D_h are configured with value 0547h.

Digital inputs

Digital input ports, registers 2F_h, 31_h and 33_h, are configured with value 1000h.

The trigger level is set by a DAC: for 1.5 V, registers 6F_h, 71_h and 73_h are configured with value 0999h.