Reference Manual DOC. REV. 01/24/2008 VCM-DAS-3 Analog Output & Digital I/O Module for the PC/104 Bus WWW.VERSALOGIC.COM 3888 Stewart Road Eugene, OR 97402 (541) 485-8575 Fax (541) 485-5712 Contents Copyright ©2008 All Rights Reserved Notice: Although every effort has been made to ensure this document is error-free, VersaLogic makes no representations or warranties with respect to this product and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. VersaLogic reserves the right to revise this product and associated documentation at any time without obligation to notify anyone of such changes. PC/104 and the PC/104 logo are trademarks of the PC/104 Consortium. MVCMDAS3 VCM-DAS-3 Reference Manual ii Product Release Notes Rev 2 Release Production release. Rev 1 Release Alpha. No customer release. Support Page The VCM-DAS-3 support page, at http://www.VersaLogic.com/private/vcmdas3support.asp, contains additional information and resources for this product including: Reference Manual (PDF format) Operating system information and software drivers Data sheets and manufacturers’ links for chips used in this product BIOS information and upgrades Utility routines and benchmark software Note: This is a private page for VCM-DAS-3 users that can be accessed only be entering this address directly. It cannot be reached from the VersaLogic homepage. VCM-DAS-3 Reference manual iii Contents Introduction ..................................................................................................................... 1 Description.......................................................................................................................... 1 Technical Specifications ..................................................................................................... 2 RoHS Compliance .............................................................................................................. 3 About RoHS........................................................................................................... 3 Warnings............................................................................................................................. 3 Electrostatic Discharge .......................................................................................... 3 Technical Support ............................................................................................................... 4 Repair Service........................................................................................................ 4 Physical Description ....................................................................................................... 5 Dimensions ......................................................................................................................... 5 Side Profile ............................................................................................................ 6 External Connectors............................................................................................................ 6 Connector Locations .............................................................................................. 6 Connector Functions and Interface Cables ............................................................ 7 J1 I/O Connector.................................................................................................... 8 J2 I/O Connector.................................................................................................... 9 J3 I/O Connector.................................................................................................. 10 Installation ........................................................................................................................ 11 Hardware Assembly............................................................................................. 11 Stack Arrangement Example ............................................................................... 11 Configuration................................................................................................................. 12 Jumper Blocks................................................................................................................... 12 Jumpers As-Shipped Configuration..................................................................... 12 Jumper Summary ................................................................................................. 13 Base Address Configuration ............................................................................................. 14 Bit Mode Configuration.................................................................................................... 15 Enhanced Mode Configuration ......................................................................................... 15 Power-up Span Range Configuration ............................................................................... 15 Registers........................................................................................................................ 16 I/O Port Mapping .............................................................................................................. 16 I/O Port Register Functions ................................................................................. 17 Enhanced Mode Registers................................................................................................. 18 Enhanced Control Register .................................................................................. 18 Enhanced Mode Data Registers ........................................................................... 19 Digital I/O Control Register.............................................................................................. 20 Digital I/O Data Registers................................................................................................. 21 Digital Input Registers ......................................................................................... 21 Digital Output Registers ...................................................................................... 22 External Trigger Enable Register...................................................................................... 23 Analog Output Data Registers .......................................................................................... 24 VCM-DAS-3 Reference Manual iv Contents DAC Channel Select Register.............................................................................. 24 DAC Write Registers ........................................................................................... 25 DAC Read Registers ............................................................................................ 25 Analog Output ............................................................................................................... 26 Analog Output Ranges and Resolution............................................................................. 26 Setting a Span Range ........................................................................................... 26 Analog Output Data Representation ................................................................................. 27 Straight Binary Coding ........................................................................................ 27 Offset Binary Coding........................................................................................... 28 Analog Output Programming............................................................................................ 30 External Trigger Update ...................................................................................... 30 Load DAC Operation........................................................................................... 30 Analog Output Code Example .......................................................................................... 31 Calibration ........................................................................................................................ 33 Setting the Gain ................................................................................................... 33 Reading the Gain ................................................................................................. 33 Enhanced Mode Operations.............................................................................................. 34 Reading DAC Data .............................................................................................. 34 Reading the Span of a Channel............................................................................ 34 Setting a Channel to Sleep Mode......................................................................... 35 Reading the Sleep Status of a Channel ................................................................ 35 Digital I/O ....................................................................................................................... 36 Signal Direction ................................................................................................................ 36 Signal Polarity .................................................................................................................. 36 Digital Input...................................................................................................................... 36 Digital Output ................................................................................................................... 36 References..................................................................................................................... 37 VCM-DAS-3 Reference manual v Introduction 1 Description The VCM-DAS-3 is a PC/104-format data acquisition board that provides analog outputs and digital I/O for process control and other applications. Its features include: 16 analog voltage outputs with 12-bit resolution Software calibration 16-bit or 8-bit ISA modes Multiple output ranges Read-back of DAC and SPAN codes Software adjustable output ranges per channel Reset/power up to 0V outputs for all ranges Simultaneous or individual DAC update External trigger Power-up ranges set by jumpers in groups of eight, reset per channel by software +5V operation 24-channel digital I/O The VCM-DAS-3 module provides 16 single-ended analog outputs and 24 digital I/O channels. Fully compatible at the register and connector level with the Diamond Systems Ruby-MM DAC board, VCM-DAS-3 also provides enhanced mode operation that extends its capabilities. In enhanced mode: Analog output ranges can be set for individual channels through software. Analog output and ranges can be read from individual channels. Specific analog channels can be placed into sleep mode to conserve power. Individual channels can be updated and read. Calibration can be performed with software. VCM-DAS-3 Reference Manual 1 Technical Specifications Technical Specifications Specifications are typical at 25°C with 5.0V supply unless otherwise noted. Board Size: 3.55” x 3.775” (PC/104 standard) Storage Temperature: -40° C to +85° C Operating Temperature: -40° C to +85° C Power Requirements: 5V ± 10% Analog Output: Channels: Resolution: Output Ranges: Output Current: Settling Time: Accuracy: Integral Nonlinearity: Differential Nonlinearity: Calibration: Gain Temp. Coefficient: Update Method: Reset: 16 outputs 12 bits Bipolar: ±10V, ±5V, ±2.5V, -2.5V to 7.5V Unipolar: 0 - 10V, 0 - 5V ±5 mA max per channel 8 uS Typ. (±10V Range, 20V Step to ±1LSB) ±1 LSB ±1 LSB ±1 LSB One gain and one zero adjustment for all channels ±2 ppm/° C Simultaneous, individual, or external trigger Outputs reset to 0V when board is jumpered for Enhanced Mode, mid-scale otherwise Digital I/O: Channels: Compatibility: Low Input Voltage: High Input Voltage: Low Output Voltage: High Output Voltage: Output Current: Pull-up Resistor: Reset: 24 CMOS / TTL, 82C55 Mode 0 only -0.3V min., 0.8V max 2.0V min., 5.5V max. 0.4V max. 3.0V max. +4 mA / -8 mA max. 10 K Ohm All channels set to input mode Software: Operating Systems: Compatible with most X86 operating systems including Windows 95/85/NT/CE/XP, QNX, VxWorks, and Linux Driver Support: No native drivers. Fully compatible with Diamond Systems drivers. Compatibility: PC/104 – Full compliance, 8-bit and 16-bit Weight: 0.152 lbs (0.069 kg) Specifications are subject to change without notice. VCM-DAS-3 Reference Manual 2 RoHS Compliance RoHS Compliance The VCM-DAS-3 is RoHS-compliant. ABOUT ROHS In 2003, the European Union issued Directive 2002/95/EC regarding the Restriction of the use of certain Hazardous Substances (RoHS) in electrical and electronic equipment. The RoHS directive requires producers of electrical and electronic equipment to reduce to acceptable levels the presence of six environmentally sensitive substances: lead, mercury, cadmium, hexavalent chromium, and the presence of polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) flame retardants, in certain electrical and electronic products sold in the European Union (EU) beginning July 1, 2006. VersaLogic Corporation is committed to supporting customers with high-quality products and services meeting the European Union’s RoHS directive. Warnings ELECTROSTATIC DISCHARGE Warning! Electrostatic discharge (ESD) can damage circuit boards, disk drives and other components. The circuit board must only be handled at an ESD workstation. If an approved station is not available, some measure of protection can be provided by wearing a grounded antistatic wrist strap. Keep all plastic away from the board, and do not slide the board over any surface. After removing the board from its protective wrapper, place the board on a grounded, static-free surface, component side up. Use an antistatic foam pad if available. The board should also be protected inside a closed metallic anti-static envelope during shipment or storage. VCM-DAS-3 Reference Manual 3 Technical Support Technical Support If you are unable to solve a problem after reading this manual please visit the VCM-DAS-3 Product Support web page at http://www.VersaLogic.com/private/vcmdas3support.asp. If you have further questions, contact VersaLogic technical support at (541) 485-8575. VersaLogic technical support engineers are also available via e-mail at [email protected]. VCM-DAS-3 Support Website http://www.VersaLogic.com/private/vcmdas3support.asp REPAIR SERVICE If your product requires service, you must obtain a Returned Material Authorization (RMA) number by calling (541) 485-8575. Please provide the following information: Your name, the name of your company and your phone number The name of a technician or engineer that can be contacted if any questions arise. Quantity of items being returned The model and serial number (barcode) of each item A detailed description of the problem Steps you have taken to resolve or recreate the problem The return shipping address Warranty Repair All parts and labor charges are covered, including return shipping charges for UPS Ground delivery to United States addresses. Non-warranty Repair All non-warranty repairs are subject to diagnosis and labor charges, parts charges and return shipping fees. Please specify the shipping method you prefer and provide a purchase order number for invoicing the repair. Note: VCM-DAS-3 Reference Manual Please mark the RMA number clearly on the outside of the box before returning. 4 Physical Description 2 Dimensions 3.05 0.15 The VCM-DAS-3 complies with all PC/104 standards. Dimensions are given below to help with pre-production planning and layout. 3.575 3.375 = Pin 1 3.15 3.3625 –0.1875 0.00 0.00 -0.20 Figure 1. Dimensions and Mounting Holes (Not to scale. All dimensions in inches.) VCM-DAS-3 Reference Manual 5 External Connectors SIDE PROFILE 0.44 0.44 0.06 Figure 2. Side Profile (Not to scale. All dimensions in inches.) External Connectors CONNECTOR LOCATIONS J3 J1 1 2 9 10 1 2 J2 1 2 V1 V2 39 V3 40 J5 B1 A1 B32 A32 C0 D0 49 50 C19 D19 J4 = Pin 1 Figure 3. Connector Locations (Top) (Not to scale.) VCM-DAS-3 Reference Manual 6 External Connectors PC/104 (ISA) pass-through male B1 A1 B19 A19 C0 D0 C19 D19 = Pin 1 Figure 4. Connector Locations (Bottom) (Not to scale.) CONNECTOR FUNCTIONS AND INTERFACE CABLES Table 1 provides information about the function, mating connectors, and transition cables for VCM-DAS-3 connectors. Page numbers indicate where a detailed pinout is available. Table 1: Connector Functions and Interface Cables Connector Function Mating Connector Digital I/O (A0A7) Analog Outputs, Digital I/O (B0C7) FCI 89361-710LF J3 Analog Outputs, Digital I/O Standard 0.1” 50-pin cable-mount IDC J4 Factory use only J5 PC/104 J1 J2 VCM-DAS-3 Reference Manual FCI 89361-740LF – AMP 1375795-2 Transition Cable – Cable Description Page 2mm 10-pin IDC 8 CBR-4004A 12” 2mm 40-pin to 40-pin IDC to screw terminal board CBR4004B Diamond Systems Data acquisition, 50 C-50-18 conductor 0.1" ribbon cable – – – – 9 10 – – 7 External Connectors J1 I/O CONNECTOR The J1 I/O connector incorporates digital I/O signals A0 through A7. The pinout of the connector is shown in Table 2. Table 2 J1 I/O Connector Pinout VCM-DAS-3 Reference Manual J1 Pin Signal Name Function 1 2 3 4 5 6 7 8 9 10 Ground DIO A7 DIO A6 DIO A5 DIO A4 DIO A3 DIO A2 DIO A1 DIO A0 Ground Ground Digital I/O A7 Digital I/O A6 Digital I/O A5 Digital I/O A4 Digital I/O A3 Digital I/O A2 Digital I/O A1 Digital I/O A0 Ground 8 External Connectors J2 I/O CONNECTOR The J2 I/O connector incorporates analog voltage outputs 0 through 15 and digital I/O channels B0 through C7. Table 3 illustrates the function of each pin and the pinout assignments to connectors on the CBR-4004 I/O board. Table 3: J2 I/O Connector Pinout J2 Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Signal Name VOUT 00 VOUT 01 VOUT 02 VOUT 03 Ground VOUT 04 VOUT 05 VOUT 06 VOUT 07 Ground VOUT 08 VOUT 09 VOUT 10 VOUT 11 Ground VOUT 12 VOUT 13 VOUT 14 VOUT 15 Ground DIO B7 DIO B6 DIO B5 DIO B4 Ground DIO B3 DIO B2 DIO B1 DIO B0 Ground DIO C7 DIO C6 DIO C5 DIO C4 Ground DIO C3 DIO C2 DIO C1 DIO C0 Ground Function Analog Out Ch 0 Analog Out Ch 1 Analog Out Ch 2 Analog Out Ch 3 Ground Analog Out Ch 4 Analog Out Ch 5 Analog Out Ch 6 Analog Out Ch 7 Ground Analog Out Ch 8 Analog Out Ch 9 Analog Out Ch 10 Analog Out Ch 11 Ground Analog Out Ch 12 Analog Out Ch 13 Analog Out Ch 14 Analog Out Ch 15 Ground Digital I/O B7 Digital I/O B6 Digital I/O B5 Digital I/O B4 Ground Digital I/O B3 Digital I/O B2 Digital I/O B1 Digital I/O B0 Ground Digital I/O C7 Digital I/O C6 Digital I/O C5 Digital I/O C4 Ground Digital I/O C3 Digital I/O C2 Digital I/O C1 Digital I/O C0* Ground CBR-4004 Connector J1 Analog Output J2 Analog Output J3 Analog Output J4 Analog Output J6 Digital I/O B J7 Digital I/O B J8 Digital I/O C J9 Digital I/O C CBR-4004 Pin (Label) 5 (IO1) 4 (IO2) 3 (IO3) 2 (IO4) 1 (GND1) 5 (IO5) 4 (IO6) 3 (IO7) 2 (IO8) 1 (GND1) 5 (IO9) 4 (IO10) 3 (IO11) 2 (IO12) 1 (GND2) 5 (IO13) 4 (IO14) 3 (IO15) 2 (IO16) 1 (GND2) 5 (IO17) 4 (IO18) 3 (IO19) 2 (IO20) 1 (GND3/PBRST#) 5 (IO21) 4 (IO22) 3 (IO23) 2 (IO24) 1 (GND3) 5 (IO25) 4 (IO26) 3 (IO27) 2 (I028) 1 (GND4) 5 (IO29) 4 (IO30) 3 (IO31) 2 (IO32) 1 (GND4) * Pin 39 can also used as an external trigger for updating DAC channels. See External Trigger Update. VCM-DAS-3 Reference Manual 9 External Connectors J3 I/O CONNECTOR The J3 I/O connector incorporates analog voltage outputs 0 through 15 and digital I/O channels A0 through C7. The pinout of the connector is shown in Table 4. Note This connector is compatible with Diamond Systems’ cable C-50-18. Any standard 0.1” 50-pin cable-mount IDC connector will mate with this connector. Table 4: J3 I/O Connector Pinout J3 Pin Signal Name Function J3 Pin 1 Ground Ground 26 2 VOUT 00 Analog Output 0 27 3 Ground Ground 28 4 VOUT 01 Analog Output 1 29 5 Ground Ground 30 6 VOUT 02 Analog Output 2 31 7 Ground Ground 32 8 VOUT 03 Analog Output 3 33 Signal Name Function Digital I/O A6 Digital I/O A5 Digital I/O A4 Digital I/O A3 Digital I/O A2 Digital I/O A1 Digital I/O A0 Digital I/O B7 Digital I/O B6 Digital I/O B5 Digital I/OB4 Digital I/O B3 Digital I/O B2 Digital I/O B1 Digital I/O B0 Digital I/O C7 Digital I/O C6 Digital I/O C5 Digital I/O C4 Digital I/O C3 Digital I/O C2 Digital I/O C1 Digital I/O C0* 21 VOUT 12 Analog Output 12 46 22 VOUT 13 Analog Output 13 47 23 VOUT 14 Analog Output 14 48 DIO A6 DIO A5 DIO A4 DIO A3 DIO A2 DIO A1 DIO A0 DIO B7 DIO B6 DIO B5 DIO B4 DIO B3 DIO B2 DIO B1 DIO B0 DIO C7 DIO C6 DIO C5 DIO C4 DIO C3 DIO C2 DIO C1 DIO C0 24 VOUT 15 Analog Output 15 49 V5_0 Protected +5.0 Volts 25 DIO A7 Digital I/O A7 50 Ground Ground 9 Ground Ground 34 10 VOUT 04 Analog Output 4 35 11 Ground Ground 36 12 VOUT 05 Analog Output 5 37 13 Ground Ground 38 14 VOUT 06 Analog Output 6 39 15 Ground Ground 40 16 VOUT 07 Analog Output 7 41 17 VOUT 08 Analog Output 8 42 18 VOUT 09 Analog Output 9 43 19 VOUT 10 Analog Output 10 44 20 VOUT 11 Analog Output 11 45 * Pin 48 can also used as an external trigger for updating DAC channels. See External Trigger Update. VCM-DAS-3 Reference Manual 10 Installation Installation HARDWARE ASSEMBLY The VCM-DAS-3 uses pass-through PC/104 (ISA) connectors so that expansion modules can be added to the top or bottom of the stack. PC/104 modules must not be positioned between the CPU board and any PC/104-Plus (PCI) modules on the stack. The entire assembly can sit on a table top or be secured to a base plate. When bolting the unit down, make sure to secure all four standoffs to the mounting surface to prevent circuit board flexing. Standoffs are secured to the top circuit board using four pan head screws. Standoffs and screws are available as part number VL-HDW-101. An extractor tool is available (part number VL-HDW-201) to separate the PC/104 modules from the stack. Use caution when using the extractor tool not to damage any board components. STACK ARRANGEMENT EXAMPLE Figure 5. Stack Arrangement VCM-DAS-3 Reference Manual 11 Configuration 3 Jumper Blocks JUMPERS AS-SHIPPED CONFIGURATION V1 V2 V3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Figure 6. Jumper Block Locations VCM-DAS-3 Reference Manual 12 Jumper Blocks JUMPER SUMMARY Table 5: Jumper Summary Jumper Block V1[15-16] Description Bit Mode Selector In Out = = As Shipped Page In 15 In 15 Out, Out, In, In, In, In, 15 16-bit ISA Transactions 8-bit ISA Transactions 8-bit mode forces the VCM-DAS-3 to respond with 8-bit transactions. This mode is required when using the board on an 8-bit bus. The 16-bit mode allows both 8 and 16-bit transactions. V1[13-14] Enhanced/Compatible Mode Selector In Out = = Enhanced Mode Compatible Mode Enhanced mode provides extra DAC functions, which should operate properly in applications designed for the Diamond Systems Ruby-MM board. V1 [11-12] to [1-2] V2 Base Address Selector – A base address of 0x000 to 0x3F0 can be selected. The last digit is always 0. First Digit 0 1 2 3 Second Digit 0 1 2 3 4 5 6 7 8 9 A B C D E F [11-12] In Out Out Out [7-8] In In In In In In In In Out Out Out Out Out Out Out Out 9-10] Out In In Out [5-6] In In In In Out Out Out Out In In In In Out Out Out Out (0x300) [3-4] In In Out Out In In Out Out In In Out Out In In Out Out [1-2] In Out In Out In Out In Out In Out In Out In Out In Out In, In, In, In A/D Channel 0-7 Span Range Selector 0V to +5V 0V to +10V -5V to +5V -10V to +10V -2.5V to +2.5V -2.5V to +7.5V [7-8] In In In In In In [5-6] In In In In Out Out [3-4] In In Out Out In In [1-2] In Out In Out In Out 26 (0V to +5V) These jumpers set the initial power up span ranges for A/D channels 0-7. V3 In, In, In, In A/D Channel 8-16 Span Range Selector 0V to +5V 0V to +10V -5V to +5V -10V to +10V -2.5V to +2.5V -2.5V to +7.5V [7-8] In In In In In In [5-6] In In In In Out Out [3-4] In In Out Out In In [1-2] In Out In Out In Out 26 (0V to +5V) These jumpers set the initial power up span ranges for A/D channels 8-16. VCM-DAS-3 Reference Manual 13 Base Address Configuration Base Address Configuration As shipped, the VCM-DAS-3 is configured for a base address of 0x300. The card occupies up to 16 consecutive I/O addresses in enhanced mode (only eight I/O addresses in compatible mode). Jumper block V1[11-12] through V1[1-2] is used set the base address. The base address can be configured from 0x000 to 0x3F0 on any 10h address boundary. Figure 7 shows how to set the address selector jumpers for the appropriate upper and middle hex digits of the three digit base address (for example, the “3” and “1” of base address 0x310). Upper Digit Middle Digit Lower Digit 9 10 1 2 11 12 3 4 5 6 7 8 The lower digit is always 0. 0 0 6 C 0x340 Example: 1 2 1 7 D 3 2 8 3 9 4 A 5 B E 1 2 3 4 5 6 7 8 9 10 11 12 F Figure 7. Base Address Jumpers VCM-DAS-3 Reference Manual 14 Bit Mode Configuration Bit Mode Configuration The VCM-DAS-3 can operate using 8-bit or16-bit ISA transactions. For compatibility with 8-bit ISA buses, you must set the VCM-DAS-3 to use 8-bit ISA transactions. Jumper V1[15-16] selects the bit mode. When a jumper is present, the board will operate on either 16-bit or 8-bit ISA bus. When the jumper is removed, the board is forced to perform only 8-bit ISA transactions. The default setting is jumper installed. Enhanced Mode Configuration Jumper V1[13-14] enables you to select between compatible or enhanced modes. A jumper installed on V1[13-14] sets the VCM-DAS-3 to enhanced mode. When no jumper is installed, the board operates in compatible mode. The default mode is enhanced. In compatible mode, eight registers are decoded for use, including all the registers needed for DAC and DIO operations and control. These registers are identical to those provided by the Diamond Systems Ruby-MM, and enable full compatibility in applications designed with that board. In this mode, analog output ranges are determined by jumper settings (in two banks of eight registers) and are not software programmable. Enhanced mode provides three additional registers for more specific control of DAC operations. The ENH_CON register enables you to set spans for specific DAC channels, read DAC data and spans, set DAC channels to sleep mode for power savings, and set and read the gain for all channels. Power-up Span Range Configuration Jumper block V2 sets the initial span range for A/D channels 7-0. Jumper block V3 sets the initial span range for A/D channels 15-8. (See Table 5 for a list of settings.) The span range can be set differently for each 8-channel bank. Within each bank, all channels will have the same initial span range; however, in enhanced mode, ranges can be set individually for each channel via software. Two unipolar output ranges (0V to 5V and 0V to 10V), and four bipolar ranges (±2.5V, ±5V, ±10V and -2.5V to 7.5V) are available. VCM-DAS-3 Reference Manual 15 4 Registers I/O Port Mapping In enhanced mode, the VCM-DAS-3 operates occupies 16 ports in the I/O map. Eleven ports are mapped to functional registers, and the remaining five ports are decoded by the board and cannot be used by other PC/104 modules. Table 6: Enhanced Mode I/O Port Addresses Write Register Read Register I/O Port Address As Shipped Address – PLDVER Base Address + F 0x30F – – Base Address + E 0x30E – – Base Address + D 0x30D – – Base Address + C 0x30C – – Base Address + B 0x30B ENCTRL ENCTRL Base Address + A 0x30A ENDATHI ENDATHI Base Address + 9 0x309 ENDATLO ENDATLO Base Address + 8 0x308 DIOCTRL DIOCTRL Base Address + 7 0x307 DIOC DIOC Base Address + 6 0x306 DIOB DIOB Base Address + 5 0x305 DIOA DIOA Base Address + 4 0x304 EXTRIG EXTRIG Base Address + 3 0x303 DACSEL – Base Address + 2 0x302 DACHI DACALL1 Base Address + 1 0x301 DACLO DACALL0 Base Address + 0 0x300 In compatible mode, the VCM-DAS-3 operates occupies eight ports in the I/O map, all of which are functional. VCM-DAS-3 Reference Manual 16 I/O Port Mapping Table 7: Compatible Mode I/O Port Addresses Write Register Read Register I/O Port Address As Shipped Address DIOCTRL DIOCTRL Base Address + 7 0x307 DIOC DIOC Base Address + 6 0x306 DIOB DIOB Base Address + 5 0x305 DIOA DIOA Base Address + 4 0x304 EXTRIG EXTRIG Base Address + 3 0x303 DACSEL – Base Address + 2 0x302 DACHI DACALL1 Base Address + 1 0x301 DACLO DACALL0 Base Address + 0 0x300 I/O PORT REGISTER FUNCTIONS The following table lists the functions assigned to each read and write I/O port register. Table 8: Register Functions Write Register Description ENCTRL Enhanced control 18 ENDATHI Enhanced Data MSB 19 ENDATLO Enhanced Data LSB 19 DIOCTRL Digital I/O control register 20 DIOC Digital I/O port C data 22 DIOB Digital I/O port B data 22 DIOA Digital I/O port A data 22 EXTRIG External trigger enable 23 DACSEL DAC channel register 24 DACHI Analog output most significant data byte (MSB). 25 DACLO Analog output least significant data byte (LSB). 25 Read Register Description ENCTRL Enhanced control 18 ENDATHI Enhanced Data MSB 19 ENDATLO Enhanced Data LSB 19 DIOCTRL Digital I/O control register 20 DIOC Digital I/O port C data 21 DIOB Digital I/O port B data 21 DIOA Digital I/O port A data 21 EXTRIG External trigger enable 23 DACALL1 Update all DACs simultaneously 25 DACALL0 Update all DACs simultaneously 25 VCM-DAS-3 Reference Manual Page Page 17 Enhanced Mode Registers Enhanced Mode Registers Setting the VCM-DAS-3 to enhanced mode enables three additional functional registers. To enable enhanced mode, install a jumper on pins V1[13-14]. ENHANCED CONTROL REGISTER ENCTRL (Write) 030Ah 7 6 5 4 3 2 1 0 CTRL3 CTRL2 CTRL1 CTRL0 SEL3 SEL2 SEL1 SEL0 Table 9: Register Bit Assignments Bit 7-4 Mnemonic CTRL Description Enhanced DAC Control – These bits select operations to be performed on specific DAC channels. CTRL3 CTRL2 CTRL1 CTRL0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 3-0 SEL VCM-DAS-3 Reference Manual 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Function Set Span: 0V to +5V Set Span: 0V to +10V Set Span: -5V to +5V Set Span: -10V to +10V Set Span: -2.5V to +2.5V Set Span: -2.5V to +7.5V (Reserved. Do not use.) (Reserved. Do not use.) Read DAC Read Span Load DAC (LDAC) DAC Sleep (Reserved. Do not use.) (Reserved. Do not use.) Set Gain Read Gain Channel Selection – These bits select the DAC channel for the operation. SEL3 SEL2 SEL1 SEL0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Channel 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 Enhanced Mode Registers ENCTRL (Read) 030Ah 7 6 5 4 3 2 1 0 – – – – – – – READY Table 10: Register Bit Assignments Bit Mnemonic 7-1 – 0 Ready Description Enhanced DAC Control Ready – Factory use only. 0 = SPI transaction in progress 1 = SPI transaction complete The internal logic of the SPI state machine is much faster than the ISA bus speed, which limits the usefulness of his bit for anything other than factory debugging of the design. ENHANCED MODE DATA REGISTERS ENDATHI MSB (Read) 0309h 7 6 5 4 3 2 1 0 D15 D14 D13 D12 D11 D10 D9 D8 ENDATLO LSB (Read/Write) 0308h 7 6 5 4 3 2 1 0 D7 D6 D5 D4 D3 D2 D1 D0 The data format of these registers depends on the operation executed in the ENCTRL register. See the sections listed below for information on data formats for specific operations. VCM-DAS-3 Reference Manual Operation CTRL Code (ENCTRL) Page Read DAC Read Span Set Gain Read Gain 08h 09h 0Eh 0Fh 34 34 33 33 19 Digital I/O Control Register Digital I/O Control Register DIOCTRL (Read/Write) 0307h 7 6 5 4 3 2 1 0 – – – DIRA DIRCHI – DIRB DIRCLO Table 11: DIOCTRL Bit Assignments Bit Mnemonic 7-5 – 4 DIRA Description Unused. These bits have no function. DIO Port A Direction – These bits control the direction of DIO port A (A7-A0). 0 = Output 1 = Input 3 DIRCHI DIO Port C MSB Direction – These bits control the direction of the upper half of DIO port C (C7-C4). 0 = Output 1 = Input 2 – 1 DIRB Unused. This bit has no function. DIO Port B Direction – These bits control the direction of DIO port B (B7-B0). 0 = Output 1 = Input 0 DIRCLO DIO Port C LSB Direction – These bits control the direction of the lower half of DIO port C (C3-C0). 0 = Output 1 = Input VCM-DAS-3 Reference Manual 20 Digital I/O Data Registers Digital I/O Data Registers DIGITAL INPUT REGISTERS DIOA (Read) 0304h D7 D6 D5 D4 D3 D2 D1 D0 DIO A7 DIO A6 DIO A5 DIO A4 DIO A3 DIO A2 DIO A1 DIO A0 DIOB (Read) 0305h D7 D6 D5 D4 D3 D2 D1 D0 DIO B7 DIO B6 DIO B5 DIO B4 DIO B3 DIO B2 DIO B1 DIO B0 DIOC (Read) 0306h D7 D6 D5 D4 D3 D2 D1 D0 DIO C7 DIO C6 DIO C5 DIO C4 DIO C3 DIO C2 DIO C1 DIO C0 Table 12: Digital Input Data Bit Assignments Bit Mnemonic 7-0 DIO A7-A0 DIO B7-B0 DIO C7-C0 Description Digital Input Data – Data read from these registers returns the current input state of the digital port signals on connectors J1 and J2. Data is not inverted. When a signal line is high, the bit reads as 1; when a signal line is low, the bit reads as 0. To operate a port in input mode, you must first set the direction of the port to input by setting the appropriate bit in the DIOCTRL register. If a port is operated in output mode, the registers can be used to read back the logic state of the output lines. Normally, the data read would be the same as the data written to the output registers; however, if an output line is stuck high or shorted to ground, the fault will be reflected in the feedback data. VCM-DAS-3 Reference Manual 21 Digital I/O Data Registers DIGITAL OUTPUT REGISTERS DIOC (Write) 0306h D7 D6 D5 D4 D3 D2 D1 D0 DIO C7 DIO C6 DIO C5 DIO C4 DIO C3 DIO C2 DIO C1 DIO C0 DIOB (Write) 0305h D7 D6 D5 D4 D3 D2 D1 D0 DIO B7 DIO B6 DIO B5 DIO B4 DIO B3 DIO B2 DIO B1 DIO B0 DIOA (Write) 0304h D7 D6 D5 D4 D3 D2 D1 D0 DIO A7 DIO A6 DIO A5 DIO A4 DIO A3 DIO A2 DIO A1 DIO A0 Table 13: Digital Output Data Bit Assignments Bit D7-D0 Mnemonic DIO A7-A0 DIO B7-B0 DIO C7-C0 Description Digital Output Data – Data written to these registers is driven onto the digital port signals on connectors J1 and J2. Data is not inverted. When a bit is set to 1, the signal line is driven high; when a bit is reset to 0, the signal line is driven low. To operate a port in output mode, you must first set the direction of the port to output by clearing the appropriate bit in the DIOCTRL register. VCM-DAS-3 Reference Manual 22 External Trigger Enable Register External Trigger Enable Register EXTRIG (Read/Write) 0303h 7 6 5 4 3 2 1 0 – – – – – – – TRIGEN Table 14: EXTRIG Bit Assignments Bit Mnemonic 7-1 – 0 TRIGEN Description Unused. These bits have no function. Trigger Enable – When the external trigger is enabled, digital I/O line C0 will update all DACs simultaneously when it is brought low. This can be done either by an external signal, when C0 is in input mode, or in software, when C0 is in output mode. If using an external trigger, make sure that the lower half of Port C is in input mode. 1 = Enable 0 = Disable VCM-DAS-3 Reference Manual 23 Analog Output Data Registers Analog Output Data Registers DAC CHANNEL SELECT REGISTER DACSEL (Write) 0302h 7 6 5 4 3 2 1 0 – – – – SEL3 SEL2 SEL1 SEL0 Table 15: DACSEL Bit Assignments Bit Mnemonic 7-4 – 3-0 SEL Description Unused. These bits have no function. Channel Selection – These bits select the DAC channel upon which digital output functions will be performed. SEL3 SEL2 SEL1 SEL0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 VCM-DAS-3 Reference Manual 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Selected Channel 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 24 Analog Output Data Registers DAC WRITE REGISTERS DACHI (Write) 0301h 7 6 5 4 3 2 1 0 – – – – DA11 DA10 DA9 DA8 DACLO (Write) 0300h 7 6 5 4 3 2 1 0 DA7 DA6 DA5 DA4 DA3 DA4 DA1 DA0 Table 16: DACHI Bit Assignments Bit Mnemonic 7-4 – 3-0 DACHI Description Unused. These bits have no function. Analog Output Data MSB – Digital-to-analog data bits DA11-DA8. DA11 is the most significant bit. This register is used with the DACLO register to form the 12-bit analog output value. Table 17: DACLO Bit Assignments Bit Mnemonic 7-0 DACLO Description Analog Output DATA LSB – Digital-to-analog data bits DA7-DA0. DA0 is the least significant bit. This register is used with the DACHI register to form the 12-bit analog output value. DAC READ REGISTERS DACALL1 (Read) 0301h 7 6 5 4 3 2 1 0 – – – – DA11 DA10 DA9 DA8 DACALL0 (Read) 0300h 7 6 5 4 3 2 1 0 DA7 DA6 DA5 DA4 DA3 DA4 DA1 DA0 Reading from these locations updates all DACs to the values written to them. Only DACs with new data written to them will change. The remaining channels will retain their current values. VCM-DAS-3 Reference Manual 25 Analog Output 5 Analog Output Ranges and Resolution VCM-DAS-3 provides six different analog output ranges (shown in Table 18), including four bipolar ranges and two unipolar ranges. One of the bipolar ranges (-2.5 to +7.5V) is asymmetrical. Power-up ranges are determined by jumper settings (see Power-up Span Range Configuration). Ranges for individual channels can be set by software using the Set Span command, available in enhanced mode. The resolution for any output range is equal to the maximum possible range of output voltages divided by the maximum number of possible steps. For a 12-bit D/A converter, the maximum number of steps is 4096. The actual output codes range from 0 to 4095, which is the full range of possible 12-bit binary numbers. (See Analog Output Data Representation.) The table below shows the analog output ranges and resolutions available on the VCM-DAS-3. Negative full scale refers to the output voltage for a code of 0, and positive full scale refers to the output voltage for a code of 4095. Table 18: Analog Output Ranges and Resolution Full-Scale Voltage Bipolar or Unipolar Range Name Negative Full Scale Positive Full Scale Resolution (1 LSB) 10V Bipolar ±10V -10V +9.9951V 4.88mV 5V Bipolar ±5V -5V +4.9963V 2.44mV 2.5V Bipolar ±2.5V -2.5V +2.4988V 1.22mV 7.5V Bipolar -2.5 to +7.5V -2.5V +7.4963V 2.44mV 10V Unipolar 0-10V 0V +9.9976V 2.44mV 5V Unipolar 0-5V 0V +4.9988V 1.22mV SETTING A SPAN RANGE Power-up span ranges are determined for blocks of channels by jumper settings (see Power-up Span Range Configuration); however, in enhanced mode, you can set the span range for any individual channel. To perform a Set Span operation: 1. Write the appropriate Set Span code (see Enhanced Control Register) to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL bits of the same register. 2. Perform an LDAC operation by writing Ah to the CTRL field of the ENCTRL register, combined with the channel number in the SEL field of the same register. VCM-DAS-3 Reference Manual 26 Analog Output Data Representation Analog Output Data Representation Two different digital coding schemes are used for analog output operations. For unipolar output ranges (positive voltages only), straight binary coding is used. For bipolar output ranges (both positive and negative voltages), offset binary coding is used. STRAIGHT BINARY CODING The formulas for calculating analog or straight binary digital values are given by: Digital = Analog Analog = Step x Digital Step Where: Analog = Applied voltage Digital = A/D conversion data Step = 0.00244140625 for 0-10V range 0.00122070313 for 0-5V range 0.0006103515625 for 0-2.5V range Table 19: Straight Binary Data Format 0-2.5V Range 0-5V Range 0-10V Range +2.5000 Hex +5.0000 +10.0000 – +2.4993 +4.9987 +9.9975 FFFh 4095 Maximum positive voltage +1.2500 +2.5000 +5.0000 800h 2048 Positive half scale +0.6250 +1.2500 +2.5000 400h 1024 Positive quarter scale +0.00061 +0.00122 +0.00244 001h 1 Positive 1 LSB 0.0000 0.0000 0.0000 000h 0 Zero (ground output) VCM-DAS-3 Reference Manual Decimal – Comment Out of range 27 Analog Output Data Representation OFFSET BINARY CODING The formulas for calculating analog or straight binary digital values are given by: Digital = Analog Step + Offset1 Analog = (Step x Digital) - Offset2 Where: Analog = Applied voltage Digital = A/D conversion data Offset1 = 2048 for symmetrical ranges 1024 for asymmetrical range Step = 0.00122070313 for ±2.5V range 0.00244140625 for ±5V and -2.5 to +7.5 ranges 0.0048828125 for ±10V range Offset2 = 2.5 for ±2.5V and -2.5 to +7.5 ranges 5 for ±5V 10 for ±10V range Table 20: Offset Binary Data Format – Symmetrical Ranges ±2.5V Output Voltage ±5V Output Voltage ±10V Output Voltage Hex Decimal – Comment +2.5000 +5.0000 +10.0000 – +2.4987 +4.9975 +9.9951 FFFh +1.2500 +2.5000 +5.0000 C00h 3072 Positive half scale +0.6250 +1.2500 +2.5000 A00h 2560 Positive quarter scale +0.00122 +0.00244 +0.00488 801h 2049 Positive 1 LSB 4095 Out of range Maximum positive voltage 0.0000 0.0000 0.0000 800h 2048 Zero (ground voltage) -0.00122 -0.00244 -0.00488 7FFh 2047 Negative 1 LSB -0.6250 -1.2500 -2.5000 600h 1536 Negative quarter scale -1.2500 -2.5000 -5.0000 400h 1024 Negative half scale -2.5000 -5.0000 -10.0000 000h 0 VCM-DAS-3 Reference Manual Maximum negative voltage 28 Analog Output Data Representation Table 21: Offset Binary Data Format – Asymmetrical Range -2.5 to +7.5 Output Voltage Hex Decimal – Comment +7.5000 – +7.4975 FFFh 4095 Maximum positive voltage Out of range +3.7500 A00h 2560 Positive half scale +1.8750 700h 1792 Positive quarter scale +0.00244 401h 1025 Positive 1 LSB 0.0000 400h 1024 Zero (ground voltage) -0.00244 3FFh 1023 Negative 1 LSB -0.6250 300h 768 Negative quarter scale -1.2500 200h 512 Negative half scale -2.5000 000h 0 VCM-DAS-3 Reference Manual Maximum negative voltage 29 Analog Output Programming Analog Output Programming Analog output voltages can be programmed either directly or with the use of a driver. This section describes how to modify analog output voltages directly. VCM-DAS-3 analog outputs have a resolution of 12 bits. Data is written to the board in 8-bit bytes, so two bytes must be used to write a single analog output value. These bytes are referred to as the least significant byte (LSB) and the most significant byte (MSB). When modifying analog outputs, one or multiple channels can be updated simultaneously. For this reason, the update operation is separate from the data write operation. To change an analog output on one or more channels: 1. Write the channel number to the DACSEL register at I/O port 0x302. 2. Write the LSB to the DACLO register at I/O port 0x300. 3. Write the MSB to the DACHI register at I/O port 0x301. 4. Repeat steps 1-3 for each channel to be changed. 5. Finally, update all channels simultaneously by reading the DACLO register. EXTERNAL TRIGGER UPDATE An external trigger is enabled by setting the TRIGEN bit in the EXTRIG register at I/O port 0x303. When the external trigger is enabled, digital I/O line C0 will update all DACs simultaneously when it is brought low. This can be done either by an external signal, when C0 is in input mode, or in software, when C0 is in output mode. If using an external trigger, make sure that the lower half of Port C is in input mode. When the trigger signal is low, DACs are updated as soon as new data is written to them. When the trigger signal is high, the DAC voltage outputs remain fixed, unless updated in software. LOAD DAC OPERATION The Load DAC (LDAC) operation provides a method for updating a single DAC channel. To perform the LDAC operation, write Ah to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL field of the same register. To change an analog output a single channel using the LDAC operation: 1. Write the channel number to the DACSEL register at I/O port 0x302. 2. Write the LSB to the DACLO register at I/O port 0x300. 3. Write the MSB to the DACHI register at I/O port 0x301. 4. Perform the LDAC operation for the selected channel. VCM-DAS-3 Reference Manual 30 Analog Output Code Example Analog Output Code Example The following Visual BASIC code illustrates how to operate the analog output feature of the VCM-DAS-3. FUNCTION LIB_das3aout (BYVAL channel, BYVAL range, BYVAL voltage) ' 'Description: This function performs an ' analog output operation to the ' specified channel. ' 'Entry: channel: analog output channel (0 to 15) ' range: 0=5V, 1=10V, 2=+/-5V, 3=+/-10V ' 4=2.5V, 5=-2.5V/+7.5V ' voltage: analog output voltage (within range) ' 'Returns: 0 if no errors ' 1 if timeout occurs ' 'Examples: 'Output +5.000V on channel 0 ' x = LIB_das3aout (0,1,5.000) ' ' 'Output -7.500V on channel 1 ' x = LIB_das3aou (1, 3, -7.500) ' 'Enhanced Control Register (BASE + 0xA) ' D7 D6 D5 D5 D3 D2 D1 D0 ' EC3 EC2 EC1 EC0 ---DAC CHANNEL--' ===================================== ' 0V to +5V 0 0 0 0 ' 0V to +10V 0 0 0 1 ' -5V to +5V 0 0 1 0 ' -10V to +10V 0 0 1 1 '-2.5V to +2.5V 0 1 0 0 '-2.5V to +7.5V 0 1 0 1 DIM DIM DIM DIM DIM DIM DIM DIM value AS INTEGER hidac AS INTEGER lodac AS INTEGER done AS INTEGER y AS INTEGER x AS INTEGER bipolar AS INTEGER fullscale AS SINGLE SELECT CASE range CASE 0 '+5V bipolar = 0 fullscale = 5 CASE 1 '+10V bipolar = 0 fullscale = 10 CASE 2 '+/-5V bipolar = 1 fullscale = 5 VCM-DAS-3 Reference Manual 31 Analog Output Code Example CASE 3 '+/-10V bipolar = 1 fullscale = 10 CASE 4 '+/-2.5V bipolar = 1 fullscale = 2.5 CASE 5 '+7.5/-2.5V bipolar = 2 fullscale = 7.5 END SELECT IF bipolar = 1 THEN 'offset binary coding (symetrical ratio) value = INT((voltage / fullscale) * 2048 + 2048) ELSEIF bipolar = 2 THEN 'offset binary coding (asymetrical ratio) value = INT((voltage / fullscale) * 3072 + 1024) ELSE 'Unipolar 'straight binary coding value = INT((voltage / fullscale) * 4096) END IF 'Limit excursion IF value > 4095 THEN value = 4095 END IF 'Separate low byte from high nibble lodac = value AND &HFF hidac = (value AND &HF00) / 256 'Set selected DAC channel to the desired range '(ENHANCED MODE REGISTER) OUT BASE + &HA, ((range * 16) + channel) 'Set selected DAC channel to desired voltage OUT BASE, lodac OUT BASE + 2, channel OUT BASE + 1, hidac 'A single read updates all outputs x = INP(BASE) 'Wait for DONE or timeout before returning done = 0 y = 0 WHILE NOT done y = y + 1 IF y < 2000 THEN 'timeout done = INP(BASE + &HA) AND &H01 '(ENHANCED MODE REGISTER) ELSE LIB_das3aout = 1 EXIT FUNCTION END IF WEND LIB_das3aout = 0 END FUNCTION VCM-DAS-3 Reference Manual 32 Calibration Calibration Calibration, if desired, is accomplished by mathematical transformation in software. Gain for the board (not individual channels) can be adjusted using the ENCTRL register. Offset adjustments are not currently implemented on the board. An SPI transaction to the gain pot will take less than 10 us. However, the Gain pot takes up to 20 ms to update its EEPROM when written to. During calibration, you need to wait 2 ms after the write command before measuring the voltage of the DAC output. SETTING THE GAIN The range of gain adjustment is 24 mV. The gain is encoded using the eight bits of the ENDATLO register, so each step equals 0.094 mV. To perform the Set Gain command, write E0h to the ENCTRL register at I/O port 0x30A, and then write the gain value to the ENDATLO register at I/O port 0x308. The following procedure is recommended for setting the gain: 1. Select channel 0 by writing 0h to the DACSEL register at I/O port 0x302. 2. Output the code for 0V by writing 0h to both the DACHI and DACLO registers. 3. Using high-precision volt meter (VOM), read the voltage on channel 0. The voltage read is the offset. 4. Output the code for known voltage minus the offset to channel 0. 5. Using the VOM, read voltage on channel 0. The difference between the VOM reading and the known voltage applied in step 4 is the gain error. 6. Adjust gain pot up or down to reduce the gain error to the lowest possible amount. Note that there is no adjustment for offset error. You must accommodate for offset with software. The gain value you set is non-volatile. READING THE GAIN To perform the Read Gain operation, write F0h to the ENCTRL register at I/O port 0x30A, and then read the value of the ENDATLO register at I/O port 0x308. VCM-DAS-3 Reference Manual 33 Enhanced Mode Operations Enhanced Mode Operations The VCM-DAS-3 must be in enhanced mode to perform enhanced mode operations. READING DAC DATA Reading a DAC using the Read DAC operation does not cause the DAC to be updated, as reading the DACALL0 register does. Performing a Read DAC operation loads the DAC voltage code in the ENDATHI and ENDATLO registers. To read the voltage of a DAC: 1. Perform a Read DAC operation by writing 8h to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL field of the same register. 2. Read the ENDATHI register and then the ENDATLO register. The 12 bits of the output voltage code are offset toward the MSB, as shown below. ENDATHI MSB (Read) 0309h 7 6 5 4 3 2 1 0 D11 D10 D9 D8 D7 D6 D5 D4 ENDATLO LSB (Read) 0308h 7 6 5 4 3 2 1 0 D3 D2 D1 D0 0 0 0 0 READING THE SPAN OF A CHANNEL To read the span of a channel: 1. Perform a Read Span operation by writing 9h to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL field of the same register. 2. Read the span code from bits 3-0 of the ENDATLO register at I/O port 0x308, as shown below. ENDATLO LSB (Read) 0308h 7 6 5 4 3 2 1 0 – – – – D3 D2 D1 D0 VCM-DAS-3 Reference Manual 34 Enhanced Mode Operations SETTING A CHANNEL TO SLEEP MODE To set a DAC to sleep mode, perform a Sleep DAC operation by writing Bh to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL field of the same register. The channel remains in sleep mode until a voltage output code is written to it. READING THE SLEEP STATUS OF A CHANNEL To read the sleep status of a channel: 1. Perform a Read Span operation by writing 9h to the CTRL field of the ENCTRL register at I/O port 0x30A, combined with the channel number in the SEL field of the same register. 2. Read the SLEEPSTAT bit (bit 4) of the ENDATLO register at I/O port 0x308, as shown below. A value of 0 = awake. A value of 1 = sleep mode. ENDATLO LSB (Read) 0308h 7 6 5 4 3 2 1 0 – – – SLEEPSTAT – – – – VCM-DAS-3 Reference Manual 35 6 Digital I/O Signal Direction The 24 digital I/O port signals on the VCM-DAS-3 can be configured as inputs or outputs, in groups of eight or, in the case of port DIOC, in groups of four. Signal direction is set by manipulating the bits in the DIOCTRL register. The logic level on any digital I/O channel can be set by writing a 1 or 0 to the appropriate bit. The digital I/O interface of the VCM-DAS-3 are 82C55 Mode 0 compatibly only. Signal Polarity All digital I/O circuits on the VCM-DAS-3 are non-inverted, true logic. A high logic level is represented by a 1 in the digital I/O data registers, and a low logic level is represented by a 0. Since Opto 22 modules invert the logic sense of signals passed through them, the register-tomodule interface is negative logic. The resulting data interface levels between the VCM-DAS-3 and I/O rack modules are shown below. Data Written I/O Pin Output Modules Input Modules I/O Pin Data Read 0 (Low) Power On Voltage Present (Low) 0 1 (High) Power Off Voltage Absent (High) 1 Digital Input The logic state of the digital input channels can be read at any time by reading the DIOA, DIOB, or DIOC registers. Simply choose the correct register and read it as an 8-bit quantity. Digital Output The logic state of any digital output channel can be manipulated at any time by writing to the DIOA, DIOB, or DIOC registers. Simply choose the correct register and write the digital value as an 8-bit quantity. VCM-DAS-3 Reference Manual 36 References DAC Controller Linear Technology LTC2704 LTC2704 Datasheet PC/104 Specification PC/104 Resource Guide PC/104 Consortium PC/104-Plus Specification PC/104 Resource Guide VersaLogic Corporation General PC Documentation The Programmer’s PC Sourcebook Microsoft Press General PC Documentation The Undocumented PC Powell’s Books VCM-DAS-3 Reference Manual A 37