Problems with PCA9555...
Jorge P
Posts: 385
He all, I am having a problem getting the code from this thread working http://forums.parallax.com/showthread.php?102475-PCA9555-IO-Expander-Driver&p=719130&viewfull=1#post719130
I wired it exactly like the diagram noting the backword symbols for the LEDs and still get nothing. Can someone verify if the code works ok for them... Hope I didnt get some bad chips from digikey:blank: All five do not work.
I wired it exactly like the diagram noting the backword symbols for the LEDs and still get nothing. Can someone verify if the code works ok for them... Hope I didnt get some bad chips from digikey:blank: All five do not work.
Comments
{{ PCA9555 Driver Test By Dave Fletcher ┌────────────────────────────────────────────────────────────────────┐ │ Vdd │ │ ___ ┌────┐┌────┐ │ │ │ unconnected INT─────┤ └┘ ├───Vdd────Vdd  │ │ Vss──A1──────┤ ├───SDA────────────────┴─P14 │ │ Vss──A2──────┤ PCA9555N ├───SCL────────────────┬─P15 │ │ 00 Vdd──────┤ ├───A0─────Vss  │ │ 01 Vdd──────┤ ├─── / ──Vss 15 s1 │ │ │ 02 Vdd──────┤ ├─── / ──Vss 14 s2 Vdd │ │ 03 Vdd──────┤ ├──────Vdd 13 │ │ PORT 0 04 Vdd──────┤ ├──────Vdd 12 │ │ 05 Vdd──────┤ ├──────Vdd 11 PORT 1 │ │ 06 Vdd──────┤ ├──────Vdd 10 │ │ 07 Vdd──────┤ ├──────Vdd 09 │ │ Vss──GND─────┤ ├──────Vdd 08 │ │ └──────────┘ │ └────────────────────────────────────────────────────────────────────┘ Test Circuit Schematic 8 pin DIP isolated 1K resistors appear to work well for the LEDs along with a 3.3v Vdd. The pull up resistors on SDA/SCL are 10K. The address pins are all tied to Vss making an address of 000. Tie to Vdd to use other addresses to put more devices on the bus. NOTE: The LEDs on port 1 on the right are backwards in the diagram because the Propeller Tool doesn't seem to have the reversed LED graphic. }}I have this wired up on PPDB, using the dipswitch as the two switches used in the schematic. I wired and rewired this several times to make sure I didn't make any mistakes. This is the code provided for the program, the pca9555 driver will follow.
CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 DIRECTION = %1100_0000_0000_0000 ALL_ON = %1100_0000_0000_0000 ALL_OFF = %1111_1111_1111_1111 ALT1 = %1110_1010_1010_1010 ALT2 = %1101_0101_0101_0101 DELAY = 30 ' 1/30 second SHORT_DELAY = 60 ' 1/60 second REPEAT_COUNT = 2 FLASH_COUNT = 50 NUM_OUTPUTS = 14 NUM_SWITCHES = 2 MODE1 = %0000_0000_0000_0000 MODE2 = %0100_0000_0000_0000 MODE3 = %1000_0000_0000_0000 MODE4 = %1100_0000_0000_0000 ' hw a0-2 r/w DEVICE = %0100__000__0 OBJ io : "pca9555" 'term : "vga_text" PUB start | i, in 'term.start(16) io.start(14, 15) ' LED test is all output. 'term.str(string(13, "io.dir: ")) 'term.dec(io.setDir(DEVICE, DIRECTION)) 'term.str(string(13, "io.getDir: %")) 'term.bin(io.getDir(DEVICE), 16) io.setDir(DEVICE, DIRECTION) repeat in := io.getIn(DEVICE) & DIRECTION 'term.str(string(13, "in(bin): %")) 'term.bin(in, 16) 'term.str(string(13, "in(dec): ")) 'term.dec(in) ' Default. if in == MODE4 'term.str(string(13, "MODE4")) repeat REPEAT_COUNT io.setOut(DEVICE, ALL_OFF) repeat i from 0 to NUM_OUTPUTS io.setOut(DEVICE, !(1 << i)) waitcnt(CNT + (CLKFREQ / DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE4 quit if in <> MODE4 quit repeat i from NUM_OUTPUTS to 0 io.setOut(DEVICE, !(1 << i)) waitcnt(CNT + (CLKFREQ / DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE4 quit if in <> MODE4 quit ' Inverse. elseif in == MODE3 'term.str(string(13, "MODE3")) repeat REPEAT_COUNT io.setOut(DEVICE, ALL_ON) repeat i from 0 to NUM_OUTPUTS io.setOut(DEVICE, 1 << i) waitcnt(CNT + (CLKFREQ / DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE3 quit if in <> MODE3 quit repeat i from NUM_OUTPUTS to 0 io.setOut(DEVICE, 1 << i) waitcnt(CNT + (CLKFREQ / DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE3 quit if in <> MODE3 quit ' Flashy elseif in == MODE2 'term.str(string(13, "MODE2")) repeat i from 0 to FLASH_COUNT if (i // 2) == 0 io.setOut(DEVICE, ALT1) else io.setOut(DEVICE, ALT2) waitcnt(CNT + (CLKFREQ / SHORT_DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE2 quit ' Solid elseif in == MODE1 'term.str(string(13, "MODE1")) repeat REPEAT_COUNT io.setOut(DEVICE, ALL_ON) waitcnt(CNT + (CLKFREQ / SHORT_DELAY)) in := io.getIn(DEVICE) & DIRECTION if in <> MODE1 quitpca9555.spin
{{ PCA9555 Driver By Dave Fletcher A .600 mil DIP-24 version of this chip currently costs $1.66 US from DigiKey. Based on Minimal I2C driver 2008-01 by deSilva [URL]http://forums.parallax.com/forums/default.aspx?f=25&m=244743[/URL] }} CON INPORT0 = 0 ' Input port 0 INPORT1 = 1 ' Input port 1 OUTPORT0 = 2 ' Output port 0 OUTPORT1 = 3 ' Output port 1 POLINV0 = 4 ' Polarity Inversion port 0 POLINV1 = 5 ' Polarity Inversion port 1 CONF0 = 6 ' Configuration port 0 CONF1 = 7 ' Configuration port 1 VAR LONG scl LONG sda PUB start(_scl, _sda) scl := _scl sda := _sda PUB setDir(addr, value) return writecmd(addr, CONF0, CONF1, value) PUB getDir(addr) return readcmd(addr, CONF0, CONF1) PUB setOut(addr, value) return writecmd(addr, OUTPORT0, OUTPORT1, value) PUB getOut(addr) return readcmd(addr, OUTPORT0, OUTPORT1) PUB setPolInv(addr, value) : recvd return writecmd(addr, POLINV0, POLINV1, value) PUB getPolInv(addr) return readcmd(addr, POLINV0, POLINV1) PUB getIn(addr) : recvd return readcmd(addr, INPORT0, INPORT1) PRI writecmd(addr, cmdlow, cmdhigh, value) : status | high, low status := 0 high := (value & %1111_1111_0000_0000) >> 8 low := value & %0000_0000_1111_1111 status := _writecmd(addr, cmdlow, low) status |= _writecmd(addr, cmdhigh, high) PRI _writecmd(addr, command, value) : status engage status := snd(addr) status |= snd(command) status |= snd(value) release PRI readcmd(addr, cmdlow, cmdhigh) : retval retval := _readcmd(addr, cmdhigh) retval <<= 8 retval |= _readcmd(addr, cmdlow) PRI _readcmd(addr, command) : retval | status, high, low retval := 0 engage status := snd(addr) status |= snd(command) engage status |= snd(addr+1) retval := rcv release PRI engage ' Pulls sda to LOW whilst CLK is HIGH dira[scl]~~ outa[sda]~ ' The former two instructions need be done only once, if all is o.k. outa[scl]~~ dira[sda]~ ' Pulse sda; HIGH by pullup (default) dira[sda]~~ ' Enable = LOW outa[scl]~ ' Keep scl LOW PRI snd(by) : status status := 0 ' Send a byte (and get status: 0: ACK 1: NAK) by := (!by) >< 8 ' Reverse bits and invert pattern repeat 8 dira[sda] := by outa[scl]~~ ' Transfer on rising edge by >>= 1 outa[scl]~ ' Returns "acknowledge bit": 0 = ACK, 1 = NAK. dira[sda]~ ' release sda outa[scl]~~ ' puls-in ACK status := ina[sda] outa[scl]~ ' keep CLK low PRI release ' Assert stop condition. ' sda transits from LOW to HIGH whilst scl is HIGH dira[sda]~~ ' LOW outa[scl]~~ dira[sda]~ ' release sda (HIGH) PRI rcv : val val := 0 ' Get a byte repeat 8 outa[scl]~~ ' Request bit val <<= 1 val |= ina[sda] outa[scl]~ ' Keep CLK low PRI nak ' Send ackbit dira[sda]~~ ' LOW outa[scl]~~ ' Pulse scl outa[scl]~ ' keep CLK low dira[sda]~ ' release sda PRI ack ' Send ackbit dira[sda]~ ' HIGH outa[scl]~~ ' Pulse scl outa[scl]~ ' keep CLK low dira[sda]~ ' release sdaHelp is appreciated. I am getting activity on the SDA and SCL lines. Should I instead rewire the LED's to ground and set the IO lines to outputs? Is the code missing something?
Also, make sure you don't have something like a PCA9555A, with a different i2c address...
Can you read anything from the chip?
Edit:
The IC's are PCA9555N, I think it is time to invest in some 22awg stranded wire instead of solid. Now I will try to connect the 16Segment LED display with a couple of these and try to get a DMM schematic wired up as I2C, I'll post in the Projects section or my Blog once I get something working if anyone is interested...
Thanks for the Input Rayman.
Oh, By the way, There is no code in obex for the PCA9555 IC, if the author is still around can you add this driver and demo to OBEX?