TS-ADC24 Getting Started Sheet

Documentation from September-2008

Table of Contents

• Overview
• Hardware Description
  • Jumpers
  • AD1 Header Pin-Out
  • AD2 Header Pin-Out
  • PC/104 IO Base Address
  • Address Decode
  • Register Map
• Functional Specification
  • ADC Channels
• Software Support
  • Linux Shell Library
  • Linux Driver
• Contact Technologic Systems
• Document History

Overview

The TS-ADC24 is a 8-bit (16-bit in ARM mode) PC/104 peripheral board (standard format) that provides 24 12-bit ADC (analog to digital converter) channels with internal 512x16bit RAM-FIFO for data acquisition and analog applications.

The TS-ADC24 features two AD7266 chips with sampling rate up to 2msps each (mega samples per second), 4msps total. Each ADC chip provides 12 ADC channels, 12-bit wide each, which can be configured as 12 single ended channels or 6 differential channels. Each chip can take 2 samples at a time, allowing the board to simultaneously read 4 channels. Each sample takes about 1us to be read. 16 of the ADC channels are brought out using rugged removable screw terminal connectors. In addition, all the ADC channels can be accessed via two standard 26-pin jumper headers.

Features include:

• Two AD7266 ADC chips
• 24 channels 12-bit ADC
• Sampling rate up to 4msps
• Single ended or differential channels
• Takes 4 samples simultaneously
• Internal 512x16bit RAM-FIFO
• Jumper selectable I/O and IRQ
• PC/104 Dimensions 3.6 x 3.8 inches
• RoHS compliant
• Linux drivers available
• Jumper selectable I/O an IRQ
• PC/104 Dimensions 3.6 x 3.8 inches

Hardware Description

Jumpers

• Jumpers 1 and 2 selects 1 of 4 IO address regions;
• Jumper 3 ON selects ARM mode for interrupt sharing and 16-bit bus cycles using 64-pin PC/104 connector;
• Jumper 4 OFF selects IRQ6; Jumper 4 ON selects IRQ7;

AD1 Header Pin-Out

• ADC chip 1 has two internal ADC machines with 6 channels each: AD1 and AD3;
• AD1-0 is channel 0 of the first ADC on chip 1;
• AD2-0 is channel 0 of the second ADC on chip 1;

AD2 Header Pin-Out

• ADC chip 2 has two internal ADC machines with 6 channels each: AD2 and AD4;
• AD2-0 is channel 0 of the first ADC on chip 2;
• AD4-0 is channel 0 of the second ADC on chip 2;

PC/104 IO Base Address

Address Decode

Register Map

Functional Specification

ADC Channels

• FPGA scans ADC block of 4 channels (four channels simultaneously, two in each chip, from channel-pair 0 to channel-pair Reg.ADCCFG.NUMCHAN) as fast as it can (sampling cycle of one ADC channel takes about 1us), put data on the FIFO (Reg.ADCFIFO) and then wait 24-bit pacing clock (Reg.ADCDLY) to expire in order to start another sampling cycle;
• Reading Reg.ADCFIFO or Reg.ADCFIFO_MSB retrieves ADC data out from the internal FIFO and update internal FIFO counters and pointers. Reg.ADCFIFO_LSB and Reg.ADCFIFO_MSB enable compatibility with 8-bit PC/104 systems;
• 24-bit pacing clock=0 (Reg.ADCDLY) indicates continuous ADC scanning; 24-bit pacing clock!=0 indicates the amount of 32MHz clocks the system will wait before the next scan cycle starts;
• The minimal acceptable value to be loaded for the pacing clock register is 1us, or hex 20;
• Updating the pacing clock value requires stopping the system by writing 0 to Reg.ADCCFG.SYSCOM;
• Interrupt signal is set high/low following the behavior of the write-only register FIFO count-interrupt (Reg.ADCSTAT.FFCOUNT[9:0], default is FIFO half-full), meaning that the CPU will be interrupted when FIFO count is equal to FIFO count-interrupt (or greater) and interrupt will be automatically cleared when FIFO is less than FIFO count-interrupt;
• Interrupt generation is disabled by default and can be enabled via the enable bit Reg.ADCSTAT.INTEN;
• Size of FIFO is statically defined at 512*16bit samples;
• FIFO is half-full when FIFO_COUNT>=(512/2), FIFO is full when FIFO_COUNT=512;
• Starting the system (Reg.ADCCFG.SYSCOM) will reset the FIFO_COUNT to zero and start scanning cycles;
• Reg.ADCCFG.SYSCOM can also be used for system status read (running/stopped)
• Stopping the system (Reg.ADCCFG.SYSCOM) will stop scanning cycles. After system stop, FIFO can still be read until it is empty or system is re-initialized;
• If FIFO is full (Reg.ADCSTAT.FFFULL), then system status changes to stopped (Reg.ADCCFG.SYSSTAT), scan cycles are stopped and system waits until host restarts it via bit (Reg.ADCCFG.SYSCOM). The remaining data in the FIFO is available until the system is restarted;
• Reg.ADCSTAT.FFHEAD is initialized at hex 0 when first word is written to the FIFO, then stepped by 1 whenever a word is pulled out from the FIFO by the host until it reaches Reg.ADCSTAT.NUNCHAN. Reg.ADCSTAT.FFHEAD is re-initialized at hex 0 when it is equal to Reg.ADCSTAT.NUNCHAN;
• All the registers are 16-bit wide; registers can also be accessed as 8-bit registers; writing to a 16-bit register using 8-bit cycles requires the LSB to be written before the MSB in consecutive cycles;
• In order to synchronize the internal machine and initialize the ADC chips after power up, it is recommended to perform an initialization cycle (Reg.ADCCFG.SYSCOM) before real utilization;
• The on-board Green LED will blink whenever there is a read access to the internal ADC FIFO;

Software Support

Linux Shell Library

In order to correctly access the TS-ADC24 registers and make use of its functions, a Linux shell script library is provided. This library include routines for the ADC machine, DACs, counters, digital IO, etc. All the registers are handled using 8-bit PC/104 cycles, therefore the routines are compatible with both 8-bit and 16-bit systems. Make sure to use the right base address for 8-bit PC/104 IO cycles in your platform by editing the ISAIO8_BASE variable. A complete list of the commands available is below:

• adc_status: Returns status of ADC machine
• adc_start: Starts ADC machine
• adc_restart: Re-starts ADC machine
• adc_stop: Stops ADC machine
• adc_sedif: Returns status of ADC single ended/differential
• adc_set_sedif: Enables ADC single ended
• adc_clr_sedif: Enables ADC differential
• adc_inrng: Returns status of ADC input range
• adc_set_inrng [0-3]: Sets input range to parameter
• adc_inten: Returns status of interrupt enable
• adc_set_inten: Enables interrupt
• adc_clr_inten: Disables interrupts
• adc_set_ffcountint [0-512]: Sets fifo count for interrupt to parameter
• adc_numchan: Returns number of pair of ADC channels
• adc_set_numchan [0-7]: Sets number of pair of ADC channels to parameter
• adc_dly: Returns 24-bit ADC pacing clock
• adc_set_dly [0-16777215]: Sets 24-bit ADC pacing clock to parameter
• adc_fffull: Returns FIFO full status
• adc_ffhfull: Returns FIFO half-full status
• adc_ffcount: Returns FIFO count
• adc_ffhead: Returns channel on the head of the FIFO
• adc_fifo: Returns channel on the head of the FIFO with information
• adc_fifoh: Returns channel on the head of the FIFO
• adc_fifon [0-512]: Returns n channels from FIFO
• adc_fifoall: Returns all channels from the FIFO
• adc_fifocont: Returns all channels from the FIFO, reading continuously
  

To make the commands of the TS-ADC24 shell library available at a shell prompt, initiate a new shell process using the TS-ADC24 shell library file as the ENV variable. For example:

# export ENV=/tsadc.lib
# chroot /
# tsadchelp

Or simply source the TS-ADC24 shell library on your running shell program:

# . /tsadc.lib
# tsadchelp

• Download the TS-ADC16/24 Linux shell library for TS SBCs

Linux Driver

tsadclib1624.tar.gz

Contact Technologic Systems

16610 East Laser Drive #10
Fountain Hills, AZ 85268
TEL 1.480.837.5200
FAX 1.480.837.5300
www.embeddedARM.com
support@embeddedARM.com

Document History

• 09.12.2008: Created
• 08.25.2010: updated links in Software Support section