TS-XDIO Datasheet - Extended Digital I/O

The following is a description of the TS-XDIO port. This core is designed to implement common controller tasks that are difficult, costly (CPU intensive), or impossible to accomplish in software with regular DIO / GPIO hardware and the facilities of the 200Mhz ARM processor.

The TS-XDIO core is a GPIO core with "eXtended Digital I/O" functionality including pulse-width modulation, quadrature and edge counting, and pulse timing with IRQ/DRQ support. Each core uses around 231 FPGA logic cells on Altera architectures.

There are two TS-XDIO cores in the TS-7300 SBC and one in the TS-7260 SBC. TS-XDIO programming is done via eight-bit accesses starting at the BASE physical memory address listed for each respective core below. There are four memory locations for each core, corresponding to BASE+0, BASE+1, BASE+2, and BASE+3.

TS- XDIO port features:

• 8-pins, individually programmable as schmitt-trigger inputs, outputs, or special functions (3.3V levels)
• glitch-detector (all pins) to catch edges/pulses as short as one fast clock period without continuous software polling
• edge-counter/frequency meter (pin 7) max incoming clock period of one-half the core clock frequency
• quadrature counter (pins 6,7) with max increment / decrement rate of one-half the maximum edge-counter frequency
• Pin 5 can optionally be used as an index pulse for resetting the edge counter or quadrature counter to 0
• PWM (pulse width modulation) output on pin 4 with period between two fast clock periods and 8190 slow clock periods, with 0.02% duty cycle precision
• One-shot programmable high or low output pulse (pin 5) of duration between one fast clock period and 4095 slow clock periods
• pulse / period timer (any pin) can measure high/low pulse time or full period lengths at fast clock period resolution

Register Map:

Registers 1-3 Depend on Mode:

Programming Notes

• If quadrature index pulse is enabled, counter is reset on positive edge of index pulse if DIO data register bit 5 is set 0, negative edge if set 1
• Pulse width modulation (PWM) time is 2 + high / low time clock periods of 14.7456Mhz or 32Khz
• If using pulse width modulation (PWM) in oneshot mode (single pulse) type is high pulse (low-high-low) if DIO data register bit 4 is set 0, low pulse (high-low-high) if set 1.
• Can use 20-bit pulse timer as free-running timer by setting accumulate bit and setting pin select to PWM (pulse width modulation) output (pin 5). 14.7456Mhz counter can be enabled by watching periods, slower free running counters can be had by clever use of high-time and low-time PWM and accumulating pulse times. (e.g. high-time 1, low-time 224 creates a 65.536Khz free-running timer that overflows once every 16 seconds)
• Edge counter counts *both* edges of waveform, divide by 2 for number of periods / frequency. To count X edges and then interrupt, preload counter value with 2^16 - X and enable IRQ on overflow.
• Max / min quadrature count can be gotten by enabling IRQ / DRQ on quadrature change of direction. Max / Min is value -/+ 1 as long as IRQ / DRQ latency is less than 1 quadrature cycle time.
• Core does not reset-- registers and state remain if board undergoes reset. On power-up DIO data direction register is all 0's (inputs), but other register contents are undefined.

C API for TS-XDIO

• download the C API, source code and sample application for TS-XDIO

struct xdio;
Contains information and state for an initialized XDIO core.

open_xdio(struct xdio *x,int num);
Pass this function a pointer to an uninitialized xdio structure. Returns true on success. The "num" parameter is the zero-index core number to open.

void close_xdio(struct xdio *x);
Call this function to release the resources associated with an XDIO core.

int setClockSpeed(xdio *x,int fast);
Each XDIO core can be set to one of two clock speeds: SLOW and FAST. The actual clock period of each of these speeds depends on the model; this function returns the clock period in nanoseconds for the speed selected.

void setPinDirection(xdio *x,int pin,enum PIN_DIRECTION dir);
Each XDIO pin can be configured as either an input or as an output. Input pins are pulled high when nothing else is connected. Use this function to set the zero-indexed pin number to either INPUT or OUTPUT. Be aware that some functions automatically set certain pins to a specific direction.

void setPin(xdio *x,int pin,enum PIN_VALUE val);
Call this function to set the output value of the given pin to either LOW or HIGH. In some cases this call will not make sense, such as when the pin is an input, or under the control of another function.

int getPin(xdio *x,int pin);
This function returns the current state of the specified pin, as either LOW (0) or HIGH (1).

void initPulseTimer(xdio *x,int pin,int acc,enum PULSE_TYPE ptype);
Prepare the pulse timer to begin sampling pulses on the specified pin. It is not required that the specified pin be an input. Pass a true value for the "acc" parameter if you wish pulse times to be accumulated across each pulse, instead of only timing the last pulse. The acceptable pulse types are:
PULSE_LOW_TIME (same as NEGEDGE_TO_POSEDGE)
PULSE_HIGH_TIME (same as POSEDGE_TO_NEGEDGE)
PULSE_PERIOD_LOW (same as NEGEDGE_TO_NEGEDGE)
PULSE_PERIOD_HIGH (same as POSEDGE_TO_POSEDGE)

long long getPulseTimer(xdio *x,int sync,int reset);
Get the current value of the pulse type, optionally waiting for the end of the current pulse (may wait indefinitely) and optionally resetting the value of the pulse timer after it is read. The value returned is the number of nano-seconds (rounded to the previous clock period) the pulse timer measured for the latest pulse, or, if "acc" was set, the sum of all pulse times since last reset.

int pinLevelChanged(xdio *x,int pin);
Returns true if the specified pin has changed state since the last time this function was called for the given pin, and false otherwise.

void generatePulse(xdio *x,long long forNs);
Generate a single pulse on pin 4. The current state of the pin will be inverted for the specified number of nano-seconds, rounded to the clock period, after which the pin's state will be returned to its original value.

int startPWM(xdio *x,int freq,int microDutyCycle);
Generates a square wave on pin 4 with the given frequency in Hz (rounded to the nearest frequency attainable with the current clock speed) and duty cycle expression as 10,000ths of a percent. This pulse-wave modulation occurs continuously until stopped. This function will return true on success, or false if an invalid parameter value was passed, such as a frequency outside of the range of the current clock speed, or no duty cycle.

void pausePWM(xdio *x);
Stop generating PWM output on pin 4. The characteristics of the waveform are retained.

void resumePWM(xdio *x);
Resume generating PWM output on pin 4 using the current waveform characteristics. You should not call this function until the function startPWM has been called.

void initCounter(xdio *x,enum COUNTER_TYPE type,enum INDEX_TYPE index);
Configure the counter type to either EDGE_COUNTER (counts edges on pin 7) or QUADRATURE (counts up/down based on pin 6/7 quadrature input). The index types are either NO_RESET (do not reset the counter implicitly) or NEGEDGE_RESET or POSEDGE_RESET (reset the counter on the respective edge on pin 5).

int getQCTR(xdio *x);
Returns the current count of the edge/quadrature counter.

void setQCTR(xdio *x,int v);
Sets the edge/quadrature counter to the specified value.