altos/driver: Document setting for AO_ST7565_BIAS

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_st7565.c b/src/drivers/ao_st7565.c
index e45db4d2c6e1440d880e4e225bce8c61e4fcb91b..24b94076737b4b048924783bed84668145dab259 100644 (file)
--- a/src/drivers/ao_st7565.c
+++ b/src/drivers/ao_st7565.c
@@ -97,6 +97,10 @@ ao_st7565_setup(void)
                return;
        setup_done = true;
        ao_st7565_reset();
+       /*
+        * Should be set to one of AO_ST7565_LCD_BIAS_1_9 or
+        * AO_ST7565_LCD_BIAS_1_7
+        */
        ao_st7565_instruction(AO_ST7565_BIAS);
        ao_st7565_instruction(AO_ST7565_ADC_SELECT_NORMAL);