/*JSON{
"type" : "method",
"class" : "SPI",
"name" : "write",
"generate" : "jswrap_spi_write",
"params" : [
["data","JsVarArray",["One or more items to write. May be ints, strings, arrays, or objects of the form `{data: ..., count:#}`.","If the last argument is a pin, it is taken to be the NSS pin"]]
]
}
Write a character or array of characters to SPI - without reading the result back.
For maximum speeds, please pass either Strings or Typed Arrays as arguments.
*/
void jswrap_spi_write(JsVar *parent, JsVar *args) {
NOT_USED(parent);
IOEventFlags device = jsiGetDeviceFromClass(parent);
spi_sender spiSend;
spi_sender_data spiSendData;
if (!jsspiGetSendFunction(parent, &spiSend, &spiSendData))
return;
Pin nss_pin = PIN_UNDEFINED;
// If the last value is a pin, use it as the NSS pin
JsVarInt len = jsvGetArrayLength(args);
if (len>0) {
JsVar *last = jsvGetArrayItem(args, len-1); // look at the last value
if (jsvIsPin(last)) {
nss_pin = jshGetPinFromVar(last);
jsvUnLock(jsvArrayPop(args));
}
jsvUnLock(last);
}
// we're only sending (no receive)
if (DEVICE_IS_SPI(device)) jshSPISetReceive(device, false);
// assert NSS
if (nss_pin!=PIN_UNDEFINED) jshPinOutput(nss_pin, false);
// Write data
jsvIterateCallback(args, (void (*)(int, void *))spiSend, &spiSendData);
// Wait until SPI send is finished, and flush data
if (DEVICE_IS_SPI(device))
jshSPIWait(device);
// de-assert NSS
if (nss_pin!=PIN_UNDEFINED) jshPinOutput(nss_pin, true);
}
/*JSON{
"type" : "method",
"class" : "SPI",
"name" : "send4bit",
"generate" : "jswrap_spi_send4bit",
"params" : [
["data","JsVar","The data to send - either an integer, array, or string"],
["bit0","int32","The 4 bits to send for a 0 (MSB first)"],
["bit1","int32","The 4 bits to send for a 1 (MSB first)"],
["nss_pin","pin","An nSS pin - this will be lowered before SPI output and raised afterwards (optional). There will be a small delay between when this is lowered and when sending starts, and also between sending finishing and it being raised."]
]
}
Send data down SPI, using 4 bits for each 'real' bit (MSB first). This can be useful for faking one-wire style protocols
Sending multiple bytes in one call to send is preferable as they can then be transmitted end to end. Using multiple calls to send() will result in significantly slower transmission speeds.
*/
void jswrap_spi_send4bit(JsVar *parent, JsVar *srcdata, int bit0, int bit1, Pin nss_pin) {
NOT_USED(parent);
IOEventFlags device = jsiGetDeviceFromClass(parent);
if (!DEVICE_IS_SPI(device)) {
jsExceptionHere(JSET_ERROR, "SPI.send4bit only works on hardware SPI");
return;
}
jshSPISet16(device, true); // 16 bit output
if (bit0==0 && bit1==0) {
bit0 = 0x01;
bit1 = 0x03;
}
bit0 = bit0 & 0x0F;
bit1 = bit1 & 0x0F;
if (!jshIsDeviceInitialised(device)) {
JshSPIInfo inf;
jshSPIInitInfo(&inf);
jshSPISetup(device, &inf);
}
// we're just sending (no receive)
jshSPISetReceive(device, false);
// assert NSS
if (nss_pin!=PIN_UNDEFINED) jshPinOutput(nss_pin, false);
// send data
if (jsvIsNumeric(srcdata)) {
jsspiSend4bit(device, (unsigned char)jsvGetInteger(srcdata), bit0, bit1);
} else if (jsvIsIterable(srcdata)) {
jshInterruptOff();
JsvIterator it;
jsvIteratorNew(&it, srcdata);
while (jsvIteratorHasElement(&it)) {
unsigned char in = (unsigned char)jsvIteratorGetIntegerValue(&it);
jsspiSend4bit(device, in, bit0, bit1);
jsvIteratorNext(&it);
}
jsvIteratorFree(&it);
jshInterruptOn();
} else {
jsExceptionHere(JSET_ERROR, "Variable type %t not suited to transmit operation", srcdata);
}
jshSPIWait(device); // wait until SPI send finished and clear the RX buffer
// de-assert NSS
if (nss_pin!=PIN_UNDEFINED) jshPinOutput(nss_pin, true);
jshSPISet16(device, false); // back to 8 bit
}