Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Transceiver Registers Page 466
Shadow Register Selector
Bits [14:10] of this register must be set to 01110 to enable read/write to the LED Selector register 2 address 1Ch.
LED4 Selector
Bits [7:4] of MII register 1Ch with shadow value 01110 select the LED2 output mode.
LED3 Selector
Bits [3:0] of MII register 1Ch with shadow value 01110 select the LED1 output mode.
LED GPIO CONTROL/STATUS (PHY_ADDR = 0X1, REG_ADDR = 1CH, SHADOW 01111B)
Write Enable
During a write to this register, setting LED GPIO Control/Status register bit 15 allows writing to bits [9:0] of this register. For
reading the values of bits [9:0], perform an MDIO write with bit 15 cleared and preferred shadow values in bits [14:10]. The
next MDIO read of register address 1Ch contains the preferred Shadow register values in bits [9:0].
Shadow Register Selector
LED GPIO Control/Status register bits [14:10] must be set to 01111 to enable read/write to the LED GPIO Control/Status
register 1Ch.
LED I/O Status
LED GPIO Control/Status register bits [7:4] read back the status of the LED pin.
Table 525: LED GPIO Control/Status Register (Address 1Ch, Shadow Value 01111)
Bit Field Description Init Access
15 Write Enable • 1 = Write bits [9:0].
• 0 = Read bits [9:0].
0R/W
14:10 Shadow Register Selector 01111 = LED GPIO Control/Status register. 01111 R/W
9:8 Reserved Write as 00, ignore when read. 00 R/W
7:4 LED I/O Status
• Bit 7 = LED4 pin status.
• Bit 6 = LED3 pin status.
• Bit 4 = LED1 pin status.
• 1 = LED pin is an input.
• 0 = LED pin is an output.
0h RO
3:0 Programmable LED I/O Control
• Bit 3 = LED4 pin control.
• Bit 2 = LED3 pin control.
• Bit 1 = LED2 pin control.
• Bit 0 = LED1 pin control.
• 1 = Disable LED output.
• 0 = Enable LED output.
0h R/W
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