1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/avr/i2c_slave.h b/drivers/avr/i2c_slave.h
index 1cd0625ef..a8647c9da 100644
--- a/drivers/avr/i2c_slave.h
+++ b/drivers/avr/i2c_slave.h
@@ -22,7 +22,18 @@
 
 #pragma once
 
-#define I2C_SLAVE_REG_COUNT 30
+#ifndef I2C_SLAVE_REG_COUNT
+
+#    if defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+#        include "transport.h"
+#        define I2C_SLAVE_REG_COUNT sizeof(split_shared_memory_t)
+#    else  // defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+#        define I2C_SLAVE_REG_COUNT 30
+#    endif  // defined(USE_I2C) && defined(SPLIT_COMMON_TRANSACTIONS)
+
+#endif  // I2C_SLAVE_REG_COUNT
+
+_Static_assert(I2C_SLAVE_REG_COUNT < 256, "I2C target registers must be single byte");
 
 extern volatile uint8_t i2c_slave_reg[I2C_SLAVE_REG_COUNT];