Hi team,
The customer is using TCA8418. The schematic and their code is in the attachment. Please check the attachment.
1. Their design is as below:
(1). COL0-COL4 and ROW0-ROW3 combined to a 4*5 KEYPAD;
(2). ROW4-ROW6 and COL7-COL8 are GPI.
(3). ROW7,COL5 and COL6 are GPO. COL9 is not used.
2. Their software design:
(1). Initialize the configuration(void TCA8418_init(void)).
(2). Read the key event and clear the TCA8418 associated flag(void hand_tca8418_event(void). The void hand_tca8418_event(void) function
is called in the MCU external interrupt function.
3. Their issue:
Q1: When ROW4 is high level and then jump to the low level, the INT pin is pull down to the low level and the INT pin remains low level, it cannot be
jumped to the high level. Then TCA8418 does not work and can not generate a normal interrupt signal to inform the MCU.
The code middleware did not receive the key message. The customer's requirement is ROW4 pin is Initialized the low level, then if it be detected
the low level, then set it the high level, after followed by loop. What is the reason?
Q2: When the INT pin is pull downed to the low level, read all registers, The INT_STAT and GPIO_INT_STAT1 register values are not 0.
Then clear the INT_STAT and GPIO_INT_STAT1 register values, then the INT pin is pulled up the high level. Then TCA8418 can work fine.
Why are INT_STAT and GPIO_INT_STAT1 register values not 0 when the INT pin is pull downed to the low level?
Best Wishes,
Mickey Zhang
Asia Customer Support Center
Texas Instruments
void iic_delay(void)
{
unsigend char delaytime = 125;
while(delaytime--);
}
void TCA8418_reset(void)
{
GPIO_ResetBits(GPIOC,GPIO_Pin_10); //Pull down reset pin
iic_delay( );
iic_delay( );
iic_delay( );
iic_delay( );
GPIO_SetBits(GPIOC,GPIO_Pin_10); //Pull up reset pin
}
sendbyteto_TCA8418(xxx,xx);//write to the xx data to the xxx register
readbytefrom_TCA8418(xxx);//read the xxx register value
void TCA8418_init(void)
{
TCA8418_reset()��
iic_delay( );
iic_delay( );
iic_delay( );
iic_delay( );
sendbyteto_TCA8418(KP_GPIO1,0x0F); //write 0x0F to the KP_GPIO1 register
iic_delay( );
sendbyteto_TCA8418(KP_GPIO2,0x1F);
iic_delay( );
sendbyteto_TCA8418(GPIO_DIR1,0x80);
iic_delay( );
sendbyteto_TCA8418(GPIO_DIR2,0x60);
iic_delay( );
sendbyteto_TCA8418(GPIO_INT_EN1,0x70);
iic_delay( );
sendbyteto_TCA8418(GPIO_INT_EN2,0x80);
iic_delay( );
sendbyteto_TCA8418(GPIO_INT_EN3,0x01);
iic_delay( );
sendbyteto_TCA8418(GPIO_DAT_OUT1,0x00);
iic_delay( );
sendbyteto_TCA8418(GPIO_DAT_OUT2,0x00);
iic_delay( );
sendbyteto_TCA8418(GPIO_DAT_OUT3,0x00);
iic_delay( );
sendbyteto_TCA8418(CFG,0x53);//CFG = 0x01
iic_delay( );
}
void hand_tca8418_event(void)
{
unsigned char int_stat = 0x00;
unsigned char key_lck_ec = 0x00;
unsigned char key_event_a = 0x00;
unsigned char temp = 0x00;
unsigned char temp_cycle = 0x00;
int_stat = readbytefrom_TCA8418(INT_STAT); //read the INT_STAT register value
if(0x01 == int_stat)
{
key_lck_ec =readbytefrom_TCA8418(KEY_LCK_EC);
temp = key_lck_ec &0x0f;
if(0x01 == temp)
{
key_event_a = readbytefrom_TCA8418(KEY_EVENT_A);
MSG_DRV_SEND(MOD_KEY_ID,key_event_a); //Send the key events and parameters to middleware
}
else
{
if(temp >10)
temp = 10;
for(temp_cycle = 0;temp_cycle <temp;temp_cycle++)
{
readbytefrom_TCA8418(KEY_EVENT_A);
}
}
}
else if(0x02 == int_stat)
{
temp = readbytefrom_TCA8418(GPIO_INT_STAT1);
if(0x10 == temp)
{
temp = readbytefrom_TCA8418(GPIO_INT_LVL1);
if(0x10 == temp)
{
MSG_DRV_SEND(MOD_KEY_ID,0x65);
set_low_extio0_int( );
}
else
{
MSG_DRV_SEND(MOD_KEY_ID,0x65|0x80);
set_high_extio0_int();
}
}
readbytefrom_TCA8418(GPIO_DAT_STAT1);
readbytefrom_TCA8418(GPIO_DAT_STAT1);
readbytefrom_TCA8418(GPIO_DAT_STAT2);
readbytefrom_TCA8418(GPIO_DAT_STAT2);
readbytefrom_TCA8418(GPIO_DAT_STAT3);
readbytefrom_TCA8418(GPIO_DAT_STAT3);
}
else
{
}
sendbyteto_TCA8418(INT_STAT,0x1F);
}
unsigned char ext_status = 0x00;
void set_high_extio0_int(void)
{
ext_status |= 0x10;
sendbyteto_TCA8418(GPIO_INT_LVL1,ext_status);
}
void set_low_extio0_int(void)
{
ext_status &= 0xef;
sendbyteto_TCA8418(GPIO_INT_LVL1,ext_status);
}
