1-Wire 64-Bit Id - Motorola 56F8346 User Manual

Freescale Semiconductor, Inc.

2.3 1-Wire 64-Bit ID

A unique ID for each 56F8346EVM board is provided by the use of a 64-bit 1-Wire ID
device, Dallas Semiconductor DS2401P, designated as U6; see Figure 2-3. The device's
1-Wire interface connects to GPIO Port E 6 (PE6) through a zero ohm resistor. The 64-Bit
ID in the 1-Wire part can be used to uniquely identify the 56F8346EVM board via
software to external devices. Since the SPI #0 port and GPIO Port E are multiplexed on
the 56F8346, the GPIO Port bit 7 must be selected in software and the data bit-banged on
the 1-Wire interface. The 1-Wire ID port can be isolated from the hybrid controller, via the
MISO0 signal, by removing R84.
+3.3V
56F8346
5.1K
1-Wire 64-Bit ID
R84
MISO0/PE7
1-W DATA
0 ohm
Figure 2-3. 1-Wire 64-Bit ID Block Diagram
2-6 56F8346EVM User Manual MOTOROLA
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