as3525v2: document PLL bits and show current PLL frequency in the debug menu

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26930 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 11 insertions, 1 deletions

diff --git a/firmware/target/arm/as3525/clock-target.h b/firmware/target/arm/as3525/clock-target.h
index 96c2c264fe..1689c59448 100644
--- a/firmware/target/arm/as3525/clock-target.h
+++ b/firmware/target/arm/as3525/clock-target.h
@@ -62,10 +62,20 @@
 #if CONFIG_CPU == AS3525v2
 
 /* PLLA & PLLB registers differ from AS3525(v1)
- * so we use a setting with a known frequency */
+ * PLL bits:
+ * - bit 0-6 = F-1 (F=multiplier)
+ * - bit 7-9 = R-1 (R=divisor)
+ * - bit 10  = OD (output divider)? Divides by 2 if set.
+ * - bit 11  = unknown (no effect)
+ * - bit 12  = unknown (always set to 1)
+ * Fpll = Fin * F / (R * OD), where Fin = 12 MHz
+ */
 #define AS3525_PLLA_FREQ        240000000
 #define AS3525_PLLA_SETTING     0x113B
 
+#define AS3525_PLLB_FREQ        192000000
+#define AS3525_PLLB_SETTING     0x155F
+
 #define AS3525_FCLK_PREDIV      0
 #define AS3525_FCLK_FREQ        AS3525_PLLA_FREQ