Shift I2S input data by 1 bit (#2121)

earlephilhower · web-flow · commit bd8eb9bca220 · 2024-04-24T11:20:22.000-07:00
Fixes #2037
diff --git a/libraries/I2S/src/pio_i2s.pio b/libraries/I2S/src/pio_i2s.pio
@@ -294,6 +294,9 @@ static inline void pio_i2s_in_program_init(PIO pio, uint sm, uint offset, uint d
     pio_sm_set_pins(pio, sm, 0); // clear pins
 
     pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits - 2));
+
+    // Offset the data by 1 bit
+    pio_sm_exec(pio, sm, pio_encode_in(pio_pins, bits - 1));
 }
 
 %}
diff --git a/libraries/I2S/src/pio_i2s.pio.h b/libraries/I2S/src/pio_i2s.pio.h
@@ -378,6 +378,8 @@ static inline void pio_i2s_in_program_init(PIO pio, uint sm, uint offset, uint d
     pio_sm_set_pindirs_with_mask(pio, sm, pin_mask, pin_mask);
     pio_sm_set_pins(pio, sm, 0); // clear pins
     pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits - 2));
+    // Offset the data by 1 bit
+    pio_sm_exec(pio, sm, pio_encode_in(pio_pins, bits - 1));
 }
 
 #endif

Original file line number	Diff line number	Diff line change
`@@ -294,6 +294,9 @@ static inline void pio_i2s_in_program_init(PIO pio, uint sm, uint offset, uint d`
`294`	`294`	`pio_sm_set_pins(pio, sm, 0); // clear pins`
`295`	`295`
`296`	`296`	`pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits - 2));`
	`297`	`+`
	`298`	`+ // Offset the data by 1 bit`
	`299`	`+ pio_sm_exec(pio, sm, pio_encode_in(pio_pins, bits - 1));`
`297`	`300`	`}`
`298`	`301`
`299`	`302`	`%}`
Original file line number	Diff line number	Diff line change
`@@ -378,6 +378,8 @@ static inline void pio_i2s_in_program_init(PIO pio, uint sm, uint offset, uint d`
`378`	`378`	`pio_sm_set_pindirs_with_mask(pio, sm, pin_mask, pin_mask);`
`379`	`379`	`pio_sm_set_pins(pio, sm, 0); // clear pins`
`380`	`380`	`pio_sm_exec(pio, sm, pio_encode_set(pio_y, bits - 2));`
	`381`	`+ // Offset the data by 1 bit`
	`382`	`+ pio_sm_exec(pio, sm, pio_encode_in(pio_pins, bits - 1));`
`381`	`383`	`}`
`382`	`384`
`383`	`385`	`#endif`