Demand Peripherals     Robotics and Automation Made Easy

PATGEN4: Four bit by 4K Pattern Generator

The PATGEN4 peripheral lets you output arbitrary 4 bit patterns of up to a length of 4096 patterns. The frequency of the output and the length (1-4096) of the pattern is programmable.

 

Hardware:

The PATGEN4 peripheral uses a 4x4K block of RAM in the FPGA to store a user defined pattern. An address counter is initialized to zero and the four bit pattern at address zero is placed on the output pins. The address counter is incremented at a user defined rate. As the address counter is incremented the pattern at that address is placed on the output pins. Incrementing the address counter continues until the address reaches a user defined terminal count. The address counter is set back to zero on the count after the terminal count.

The lowest numbered pin on the connector is controlled by the LSB in the four bit patterns. PATGEN4 works with any of the following cards:
     GPIO with pin headers
     GPIO with screw terminals
     Open-Drain Driver Card

 

Resources:

pattern : the address and pattern data. This resource lets you incrementally fill the pattern RAM with data. The address is given first as a 12 bit hex value. The values starting at that address are given as a string of hex characters. You can specify up to 64 hex values with each dpset command. This resource is write-only and only works with dpset. For example, the following commands fill the first 128 four-bit nibbles with an alternating pattern of 0101 and 1010.

    dpset patgen4 pattern 000 5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a
    dpset patgen4 pattern 040 5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a

config : clock rate and maximum address. The config resource has the clock rate in Hertz followed by the maximum pattern address as a 12 bit hex value. The actual clock rate might not be exactly the value you specify. A dpget on the config resource returns the actual clock rate.

 

Examples:

Consider a hypothetical problem in which you want to send an SPI packet to a device, wait a short time, and send it again. You are ignoring the return values. MOSI is on the LSB, an active low chip enable is on the next LSB, and SCK is on the MSB. The SPI packet to send is c455, the SCK frequency should be 500 KHz, and the SPI port is Mode 0 with MSB first. The pattern clock will be at 1 MHz since it has to be twice the SCK frequency. The hex string, c455, is 1100010001010101 in binary. For each binary bit we set the data bit and the clock low, then set the clock high. Chip select goes low before the first bit and high after the last bit. Putting this all together as a set of commands to the PATGEN4 peripheral you'd get:

    dpset patgen4 pattern 000 0191908080819080808190819081908190
    dpset patgen4 pattern 022 222222222222222222222222222222
    dpset patgen config 1000000 03f

 

FPGA Defined Peripherals
User Interface
FPGA Configuration
FPGA Buttons & LEDs
Text LCD and Keypad
Quad WS2812 Interface
Quad Slide Pot
Tone Generator
IR Recv/Xmit
6 Digit LCD
RC Decoder
Keyfob RF Decoder
Rotary Encoder Interface
Motion Control
Dual DC Motor Controller
Dual Quadrature Decoder
Quad 13 Bit Servo
Bipolar Stepper Controller
Unipolar Stepper Controller
Simple Input / Output
Quad Binary Output
Quad Binary Input
Quad GPIO
Octal Input/Output
32 Channel Binary Output
32 Channel Binary Input
Sensors
Octal 12-bit ADC
Quad Ping))) Interface
Octal SRF04 Interface
Quad Event Counter
Instrumentation
Generic I2C
Generic SPI
Octal 8-Bit DAC
Quad Digital Potentiometer
Quad PWM Output
Quad PWM Input
4 Bit Pattern Generator
Real Time Clock
Dual Watchdog Timers
  

Interface Cards
User Interface
Audio Amplifier
IR Recv/xmit
Six Digit LCD Display
Keyfob RF Receiver
Rotary Encoder
Quad Switch Card
Text LCD / keypad
Quad Slide Pot
Motion Control
Dual 7-amp H-bridge
Quad Open Drain Driver
Quad 10 Amp Relay Card
Input / Output
Octal 8-Bit DAC
Quad Digital Potentiometer
Octal 12-bit ADC
9DOF IMU
Octal SRF04
Quad GPIO
Generic I2C
Generic SPI
USB 2.0 Hub
Real Time Clock
Slot Expander
Octal Input/Output
32 Channel Input
32 Channel Output
Accessories
Power Distribution Card
15 Amp Power Distribution
5 Volt Switching Regulator
ATX Power Break-Out Card
Disk Drive Power Break-Out
MP43 Aluminum Mounting Plate
WW2 Prototyping Card
WW1 Small Prototyping Card