oPossum 1,083 Posted September 26, 2011 Share Posted September 26, 2011 This is a reimplementation of adafruit's TV-B-Gone kit. It has been written from scratch to be more efficient and more precise than the AVR version. Assembly code is used for the critical timing, everything else is in C. Clock is 1 MHz (vs. 8 MHz for AVR). This code is small enough to fit in a G2231 (2K flash, 128 RAM) that comes with the launchpad. There are only 39 codes due to limited flash capacity. Obviously larger parts like the G2553 could be used to fit all codes and add additional features. main code (excerpt) void send_code(TIRCODE * const ic) { const uint8_t *code_byte; unsigned code_bitmask; static uint8_t idx[100]; // static so it is not on the stack unsigned n, j; uint8_t *p; // Make sure there is room for all indicies if(ic->pair_count > sizeof(idx)) return; // Convert variable bit count to uint8_t n = ic->pair_count; code_byte = ic->bitstream; code_bitmask = 0x80; p = idx; // Iterate indicies while(n--) { *p = 0; j = ic->bits_per_index; // Iterate bits while(j--) { *p <<= 1; if(*code_byte & code_bitmask) *p |= 4; code_bitmask >>= 1; if(!code_bitmask) ++code_byte, code_bitmask = 0x80; } ++p; } if(ic->carrier_period) { TACCR0 = ic->carrier_period; TACCR1 = ic->carrier_period >> 1; tx_ir_carrier(ic->pair_count, idx, ic->durations); } else { tx_ir_pulse(ic->pair_count, idx, ic->durations); } } void main(void) { unsigned n; WDTCTL = WDTPW + WDTHOLD; // Disable watchdog // DCOCTL = 0; // Use 1 MHz calibration BCSCTL1 = CALBC1_1MHZ; // DCOCTL = CALDCO_1MHZ; // // // See chart for I/O assignment P1OUT = 0x0E; // Txd, Rxd, S2 high P1REN = 0x0C; // Rxd / S2 pullup enabled P1DIR = 0xF3; // Rxd / S2 in, all others out P1SEL = 0x50; // Timer A T0.1 / SMCLK TACTL = TASSEL_2 | MC_1; // Clock = SMCLK, Mode = UP // do { // /// todo: Sleep while waiting for S2 press // while(P1IN & 8); // Wait for S2 press // for(n = 0; n < code_count; ++n) { // P1OUT |= 0x01; // LED on delay10us(450 * 100u); // Wait 450 ms P1OUT &= ~0x01; // LED off send_code(CodeList[n]); // Send code } // } while(1); // } ir transmission code (excerpt) tx_ir_carrier ; void tx_ir_carrier(unsigned n, uint8_t *i, TDUR *d) ; R12 Duration pair count ; R13 Pointer to duration indicies ; R14 Pointer to durations ; mov #OUTMOD_7, R10 ; IR Carrier On (reset/set output mode) mov #OUTMOD_5, R11 ; IR Carrier Off (reset output mode) ; ir_tx_loop mov.b @R13, R15 ; Get duration index add R14, R15 ; Add duration pointer mov @R15, R15 ; Get duration ; mov R10, &TACCTL1 ; Turn on IR call #delay ; Wait for on duration ; nop2 ; Precise timing ; mov.b @R13+, R15 ; Get duration index and increment pointer incd R15 ; Adjust for off duration add R14, R15 ; Add duration pointer mov @R15, R15 ; Get duration ; mov R11, &TACCTL1 ; Turn off IR call #delay ; Wait for off duration ; dec R12 ; Decrement pair count jne ir_tx_loop ; Do next duration pair... ; ret ; Return ; ; ; ; - Delay in units of 10 cycles (10 us at 1 MHz) delay cmp #4, R15 ; Compare to minimum jlo dlyret ; Below minimum, return... sub #2, R15 ; Adjust loop count for overhead jmp eloop ; Make the first iteration shorter ; delay10us mov R12, R15 ; C callable ; dloop nop2 ; 7 cycles of nop nop2 ; nop2 ; eloop nop ; dec R15 ; Decrement loop count - 1 cycle jne dloop ; Loop if not zero - 2 cycles ; dlyret ret ; Complete code attached tvbg_lp.zip jbremnant, Rickta59, dacoffey and 6 others 9 Quote Link to post Share on other sites
RobG 1,892 Posted September 26, 2011 Share Posted September 26, 2011 Any IR LED suggestions? The more power the better. Quote Link to post Share on other sites
oPossum 1,083 Posted September 28, 2011 Author Share Posted September 28, 2011 Consumer IR is 940/950 nm, so whatever LED you choose, make sure it is the proper wavelength. The IR333 type is a very common generic IR LED. It is made by many manufactures and there are a few variants of it. The exact specs and quality will vary from one mfg to another. I have been using Vishay IR LEDs - mostly TSAL6200. They have superior specs, but I don't know if that makes any real difference in the real world. Here is a list of some of the Vishay parts and two IR333 for comparison... IR333A 20 degrees TSAL6100 20 degrees TSAL5100 20 degrees TSAL6200 35 degrees TSAL7200 35 degrees IR333C/H0/L10 40 degrees TSAL5300 45 degrees TSAL7300 45 degrees TSAL6400 50 degrees TSAL7400 50 degrees TSAL7600 60 degrees I think the TASL6x00 and TSAL7x00 are the same die in a different package (tinted vs clear). A PN2222A or PZT2222A works well for driving the IR LED. The beta drops as IC (collector current) increases, so it is effectively current limited. It is a proven design (that is often questioned by those who don't understand it). An IR LED will typically handle 50 to 100 mA continuous, and 500 to 1000 mA for a short time. Most IR protocols use bursts of 30 to 60 kHz, so the IR LED can be driven near it's maximum rating. The Vf is about 1 volt (current dependent), much lower than visible LEDs. If you are developing firmware then it is a good idea to limit the current to 50 mA or less until the code is proven to work properly. I have not done any hardware for the MSP430 yet, but I have done some AVR designs that show the IR LED driver circuit. The CHiP (Compact High Power): This design fits in one compartment of a AA battery holder. It can operate at moderate power when 2 AA cells are used, or high(er) power when 3 AA cells are used. An emitter follower is used for the high power mode only. The EHP (Extereme High Power): Several adafruit forum members built this and it performs very well. It pulls about 6 amp pulses from the 4 AA cells and often makes them squeal. Keychain: Uses two CR2032 cell - one for the micro, and one for the MCU. This prevents MCU brownout while allowing max LED current. RobG, nuetron and gordon 3 Quote Link to post Share on other sites
xmob 26 Posted September 28, 2011 Share Posted September 28, 2011 My camera intervalometer project uses the Vishay TSAL7400 driven by a 2N2222. I've used these LEDs on several projects and they're practically indestructible! I second what oPossum says above. The IR LEDs can be driven at what seem like excessive currents simply because of the switching frequencies. Quote Link to post Share on other sites
RobG 1,892 Posted September 28, 2011 Share Posted September 28, 2011 Awesome, I think it's time to pay a visit to Sears and Hhgregg. Instead of power-off, I will program to send volume up nuetron 1 Quote Link to post Share on other sites
zborgerd 62 Posted September 28, 2011 Share Posted September 28, 2011 Awesome, I think it's time to pay a visit to Sears and Hhgregg. Instead of power-off, I will program to send volume up Yeowch! That's mean! Quote Link to post Share on other sites
nuetron 64 Posted September 29, 2011 Share Posted September 29, 2011 It pulls about 6 amp pulses from the 4 AA cells and often makes them squeal. That's interesting, never heard of noise-making batteries before... Instead of power-off, I will program to send volume up How much memory would it take to add another function and button? Seems to me all that would be needed is a few IF statements in certain places. Quote Link to post Share on other sites
gordon 229 Posted September 29, 2011 Share Posted September 29, 2011 That's interesting, never heard of noise-making batteries before... http://thecustomgeek.com/2011/09/13/fun ... 4-of-them/ Fun's in the video . nuetron 1 Quote Link to post Share on other sites
kenemon 29 Posted September 29, 2011 Share Posted September 29, 2011 Awesome, I think it's time to pay a visit to Sears and Hhgregg. Instead of power-off, I will program to send volume up I think shutting them all off would cause more peaceful confusion :thumbup: Quote Link to post Share on other sites
RobG 1,892 Posted September 29, 2011 Share Posted September 29, 2011 How about sending random commands, power, volume, channel, input, etc., that will be even more fun. Quote Link to post Share on other sites
lastaid 15 Posted October 26, 2011 Share Posted October 26, 2011 Could this be scaled to MSP430G2553? Then you could fit all EU or US codes on the chip, not only the most used ones. -lastaid Quote Link to post Share on other sites
gordon 229 Posted October 26, 2011 Share Posted October 26, 2011 I wish the answer was right there in the very first post. Oh, wait... Quote Link to post Share on other sites
SugarAddict 227 Posted January 12, 2012 Share Posted January 12, 2012 I've played with the AC Remote and the IR Booster of gordons with this... works amazingly great I put 5 different emitters on here to look at with the camera to determine which I wanted to use... man, I can't even point this thing AWAY from my tv without the tv going off lol bluehash 1 Quote Link to post Share on other sites
bluehash 1,581 Posted January 12, 2012 Share Posted January 12, 2012 Looks like you powered all four blocks. Quote Link to post Share on other sites
lastaid 15 Posted March 16, 2012 Share Posted March 16, 2012 has anyone altered the codes.c for the msp430g2553??? trying to implement this Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.