diff --git a/pypcc/config/RECVTR_HB.yaml b/pypcc/config/RECVTR_HB.yaml
index cade9a30e5d99894d072d0cc4c51cc50f5dbf6bf..a383885cc621b83de31a37280e77cfbe3cd47675 100644
--- a/pypcc/config/RECVTR_HB.yaml
+++ b/pypcc/config/RECVTR_HB.yaml
@@ -76,6 +76,15 @@ drivers:
 
 #This is the I2C devices in the RCU
 device_registers:
+#       7      6      5      4      3      2      1      0
+#IO1_1: P_Ant1 P_Ant0 Att0.................................
+#IO1_2  P_Ana* P_Ant2 Att1.................................
+#IO2_1: Pgood* P_Dig* Att2.................................
+#IO2_2: LED    LED    Band1.............   Band0...........
+#IO4_1: x      x      DAB2......    DAB1......    DAB0......          
+#IO4_2: LED    LED    MCLR   PGD    PGC    BAND2...........
+#IO3_1: NC     A0_P   A2_P   A2_IO  A1_P   A1_IO  A_CLK  A0_IO   
+#IO3_2: D_EN   D_SDA  D0_CLK D1_CLK D2_CLK A2_CS  A1_CS  A0_CS
  - name: IO
    dim: 4
    description: [IO-Expander for filter selection,IO-Expander for ON/OFF, Band, BUFx2,IO-Expander for ADC control]