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core: Avoid deadlock when uart.c is used in ISR

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tmk 2019-05-02 20:57:48 +09:00
parent 292cc939ec
commit 55443fabb7
1 changed files with 3 additions and 1 deletions
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4
tmk_core/common/avr/uart.c
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@ -66,7 +66,7 @@
// These buffers may be any size from 2 to 256 bytes.
#define RX_BUFFER_SIZE 64
#define TX_BUFFER_SIZE 40
#define TX_BUFFER_SIZE 256
static volatile uint8_t tx_buffer[TX_BUFFER_SIZE];
static volatile uint8_t tx_buffer_head;
@ -95,6 +95,8 @@ void uart_putchar(uint8_t c)
i = tx_buffer_head + 1;
if (i >= TX_BUFFER_SIZE) i = 0;
// return immediately to avoid deadlock when interrupt is disabled(called from ISR)
if (tx_buffer_tail == i && (SREG & (1<<SREG_I)) == 0) return;
while (tx_buffer_tail == i) ; // wait until space in buffer
//cli();
tx_buffer[i] = c;