I've also posted this in I2C topic, the solution is there: http://beagleboard.org/Community/Forums/?place=msg%2Fbeagleboard%2FDAXyYJOrDIc%2FDZ8WKkRWaC0J
Il giorno lunedì 13 luglio 2015 09:49:20 UTC+2, Gianfranco Rosso ha scritto: > > I want to manage the I2C1 module by the PRU, in order to interface some > I/O expanders (MCP23017 by Microchip). > I use may own "cape" without the plug-n' play eeprom (one of the next > steps will be adding management for DCAN0 and DCAN1 so i'll need these pins > too...). > So, at present, there are just 2 MCP23017 connected to the P9.17 and P9.18. > > I load the *cape-universal* into slots and then I use *configure-pin* > command to set P9.17 and P9.18 as *i2c* > > I've started from an example into the *am335x_pru_package-master* and > wrote my own C PRU loader. > Very simple, it just: > > - loads the PRU code > - init the data exhanged with the PRU > - start the PRU > - wait for ESC key press > - signal to the PRU to stop > - wait for the PRU stop > - exit. > > > Also the assembly PRU code is simple: > > - init I2C1 module (by writing registers PSC, SCLL, SCLH, CON) > - init 1st I/O expander as 16 inputs (even if at power on it's already > set as input) > - init 2nd I/O expander as 16 outputs > - cicle reading status of inputs from 1st expander and echoing to the > outputs of 2nd expander > - exit cycle and halt when receive stop flag from the loader > > for send and receive I2C messages I use register SA, CNT, DATA and CON. > > > That's very simple and linear... pity, it doesn't work. > > *I didn't see any activity at all in P9.17 and P9.18*. > > The PRU code is surely running, as I add a cycle counter and show it in > the loader while it's waiting for ESC keypress, and also the PRU code > correctly stops at the loader command. > > I was expecting that the PRU code stalls if I2C bus doesn't work, as there > are waiting cycles both for STOP condition or for CNT reaching zero > (depending on the write or read message sending). > > But it seems running, and running very fast also: the cycle counter is > incremented to a very fast rate (over 550 kcycles/s) that's not compatible > with the correct executing of I2C sequences (I've setted the module for > 400Kbps rate... so the PRU cycle it's even faster than a single I2C bit > time!). > > > I'm surely doing something wrong, but I cant fugure what. > > Any idea? > > Suggestions? > > > Inserisci qui il codice... > .origin 0 > .entrypoint START > > #include "iic_ioexp.hp" > > //costanti per l'accesso al modulo I2C1 > #define I2C1_BASE C2 //base registri I2C1 nella > tabella costanti > #define I2C_SYSC 0x10 //offset del registro I2C_SYSC > #define I2C_STAT_RAW 0x24 //offset del registro > I2C_STATUS_RAW > #define I2C_SYSS 0x90 //offset del registro I2C_SYSS > #define I2C_CNT 0x98 //offset del registro > I2C_CNT > #define I2C_DATA 0x9C //offset del registro I2C_DATA > #define I2C_CON 0xA4 //offset del registro > I2C_CON > #define I2C_SA 0xAC //offset del registro I2C_SA > #define I2C_PSC 0xB0 //offset del registro > I2C_PSC > #define I2C_SCLL 0xB4 //offset del registro I2C_SCLL > #define I2C_SCLH 0xB8 //offset del registro I2C_SCLH > > #define I2C_CMD_ENABLE 0x8400 //modulo I2C abilitato > come master > #define I2C_CMD_TX 0x0200 //modulo I2C in > trasmissione > #define I2C_CMD_RX 0x0000 //modulo I2C in ricezione > #define I2C_CMD_START 0x0001 //modulo I2C richiesta > generazione sequenza START > #define I2C_CMD_STOP 0x0002 //modulo I2C richiesta > generazione sequenza STOP > > > //costanti per l'accesso all'I/O expander MCP23017 > #define IO_EXP0 0x20 //7bit I2C address dell'I/O > expander 0 (ingressi) > #define IO_EXP1 0x21 //7bit I2C address dell'I/O > expander 1 (uscite) > > #define IO_EXP_IODIRA 0x00 //indirizzo registro IODIRA > dell'I/O expander > #define IO_EXP_GPIOA 0x12 //indirizzo registro GPIOA > dell'I/O expander > > //====================================================================== > > //macro che attende fine sequenza verificando generazione seqeunza di STOP > .macro I2C_WAIT_BY_STOP > _CHECK: > LBCO r1.w0, I2C1_BASE, I2C_CON, 2 > QBBS _CHECK, r1.t1 > .endm > > //macro che attende fine sequenza verificando generazione seqeunza di STOP > .macro I2C_WAIT_BY_COUNT > _CHECK: > LBCO r1.w0, I2C1_BASE, I2C_CNT, 2 > QBNE _CHECK, r1.w0, 0 > .endm > > > //====================================================================== > > START: > // clear that bit > LBCO r0, C4, 4, 4 > CLR r0, r0, 4 > SBCO r0, C4, 4, 4 > > //------------------------------------------------------------------ > //configurazione modulo I2C1 > > //reset del modulo I2C1 > MOV r1.w0, 0x0002 > SBCO r1.w0, I2C1_BASE, I2C_SYSC, 2 > > MOV r1.w0, 0x0000 > SBCO r1.w0, I2C1_BASE, I2C_SYSC, 2 > > // //attesa fine reset modulo > //_WAIT_RDONE: > // LBCO r1, I2C1_BASE, I2C_SYSS, 4 > // QBBC _WAIT_RDONE, r1.t0 > > //configura prescaler e durata SCL H/L per avere 400kHz > MOV r1.b0, 4 //prescaler=4+1 --> > ICLK=SCLK/prescaler=100/5=20MHz (nel reference manual raccomandano circa > 24Mhz) > SBCO r1.b0, I2C1_BASE, I2C_PSC, 1 > > MOV r1.b0, 18 //durata SCL L=18+7 --> > tLOW=1/ICLK*(SCLL+7)=1/20E6*(18+7)=1.25us > SBCO r1.b0, I2C1_BASE, I2C_SCLL, 1 > > MOV r1.b0, 20 //durata SCL H=20+5 --> > tHIGH=1/ICLK*(SCLH+5)=1/20E6*(20+5)=1.25us > SBCO r1.b0, I2C1_BASE, I2C_SCLH, 1 > > //abilita modulo > MOV r1.w0, I2C_CMD_ENABLE > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > //------------------------------------------------------------------ > //inizializzazione IOEXP 0 > > //indirizzo slave > MOV r1.w0, IO_EXP0 > SBCO r1.w0, I2C1_BASE, I2C_SA, 2 > > //n. byte da spedire > MOV r1.w0, 3 > SBCO r1.w0, I2C1_BASE, I2C_CNT, 2 > > //riempie FIFO > MOV r1, IO_EXP_IODIRA | 0x00FFFF00 //tutti i pin come ingressi > (in realta' e' gia' cosi' dal POR) > SBCO r1.b0, I2C1_BASE, I2C_DATA, 1 > SBCO r1.b1, I2C1_BASE, I2C_DATA, 1 > SBCO r1.b2, I2C1_BASE, I2C_DATA, 1 > > //attesa bus free > _WAIT_BB: > LBCO r1, I2C1_BASE, I2C_STAT_RAW, 4 > QBBS _WAIT_BB, r1.t12 > > //comando scrittura > MOV r1.w0, I2C_CMD_ENABLE | I2C_CMD_TX | I2C_CMD_START | I2C_CMD_STOP > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > I2C_WAIT_BY_STOP > > //------------------------------------------------------------------ > //inizializzazione IOEXP 1 > > //indirizzo slave > MOV r1.w0, IO_EXP1 > SBCO r1.w0, I2C1_BASE, I2C_SA, 2 > > //n. byte da spedire gia' impostato > > //riempie FIFO > MOV r1, IO_EXP_IODIRA | 0x00000000 //tutti pin come uscita > SBCO r1.b0, I2C1_BASE, I2C_DATA, 1 > SBCO r1.b1, I2C1_BASE, I2C_DATA, 1 > SBCO r1.b2, I2C1_BASE, I2C_DATA, 1 > > //comando scrittura > MOV r1.w0, I2C_CMD_ENABLE | I2C_CMD_TX | I2C_CMD_START | I2C_CMD_STOP > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > I2C_WAIT_BY_STOP > > > //------------------------------------------------------------------ > //ciclo rinfresco I/O > > _LOOP: > > //------------------------------------------------------------------ > //legge ingressi > > //indirizzo slave > MOV r1.w0, IO_EXP0 > SBCO r1.w0, I2C1_BASE, I2C_SA, 2 > > //n. byte da spedire > MOV r1.w0, 1 > SBCO r1.w0, I2C1_BASE, I2C_CNT, 2 > > //riempie FIFO > MOV r1, IO_EXP_GPIOA > SBCO r1.b0, I2C1_BASE, I2C_DATA, 1 > > //comando scrittura > MOV r1.w0, I2C_CMD_ENABLE | I2C_CMD_TX | I2C_CMD_START > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > I2C_WAIT_BY_COUNT > > //n. byte da ricevere > MOV r1.w0, 2 > SBCO r1.w0, I2C1_BASE, I2C_CNT, 2 > > //comando lettura > MOV r1.w0, I2C_CMD_ENABLE | I2C_CMD_RX | I2C_CMD_START | I2C_CMD_STOP > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > I2C_WAIT_BY_STOP > > //legge i byte ricevuti > LBCO r2.b1, I2C1_BASE, I2C_DATA, 1 > LBCO r2.b2, I2C1_BASE, I2C_DATA, 1 > > //------------------------------------------------------------------ > //scrive uscite > > //indirizzo slave > MOV r1.w0, IO_EXP1 > SBCO r1.w0, I2C1_BASE, I2C_SA, 2 > > //n. byte da spedire > MOV r1.w0, 3 > SBCO r1.w0, I2C1_BASE, I2C_CNT, 2 > > //riempie FIFO > MOV r2.b0, IO_EXP_GPIOA > SBCO r2.b0, I2C1_BASE, I2C_DATA, 1 > SBCO r2.b0, I2C1_BASE, I2C_DATA, 1 > SBCO r2.b0, I2C1_BASE, I2C_DATA, 1 > > //comando scrittura > MOV r1.w0, I2C_CMD_ENABLE | I2C_CMD_TX | I2C_CMD_START | I2C_CMD_STOP > SBCO r1.w0, I2C1_BASE, I2C_CON, 2 > > I2C_WAIT_BY_STOP > > //------------------------------------------------------------------ > LBCO r2, CONST_PRUDRAM, 0, 4 > ADD r2, r2, 1 > SBCO r2, CONST_PRUDRAM, 0, 4 > > //------------------------------------------------------------------ > //esce dal ciclo e se il flag di uscita nella ram condivisa e' azzerato > LBCO r2, CONST_PRUDRAM, 4, 1 > QBNE _LOOP, r2.b0, 0 > > _EXIT: > //invia all'host la notifica di programma completato > MOV R31.b0, PRU0_ARM_INTERRUPT+16 > > HALT > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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