GR4x to GR64 Migration Guide
2.2.3
UARTs
The GR64 has only two UART interfaces, unlike its predecessors which had three. For
legacy reasons the signal nomenclature has been retained, so that the original UART1
and UART3 still exist.
UART2 has been replaced by a reserved, peripheral interface.
2.2.4
Digital IO
The GM/GR4x series operated 2.78V digital IO. The newer technology of the GR64
utilizes 1.8V logic. To overcome interface difficulties with legacy applications, the
GR64 has level shifters on each of the IO interfaces.
The legacy variant GR64 references an internal 2.8V regulator, performing the
necessary bi-directional level translation. Some modification to existing user
interface circuitry may be necessary due to the internal impedance of the level shifters
themselves; this is detailed in a subsequent section.
The integrated SIM variant GR64 employs the same level shifters, and provides a VREF
input signal so that users can provide an application-side digital IO reference voltage
to the GR64 Wireless CPU®.
Migration Guide
This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without prior written agreement.
Ce document est la propriété exclusive de WAVECOM. Il ne peut être communiqué ou divulgué à des tiers sans son autorisation préalable
GR4x to GR64
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