XR16L788IQ-F Datasheet, PDF (25/54 Pages) Exar Corporation – HIGH PERFORMANCE 2.97V TO 5.5V OCTAL UART

REV. 1.2.3
3.1.5 RESET [7:0] (default 0x00)
XR16L788
HIGH PERFORMANCE 2.97V TO 5.5V OCTAL UART
RESET Register
Individual UART Channel Reset Enable
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
Ch-7 Ch-6 Ch-5 Ch-4 Ch-3 Ch-2 Ch-1 Ch-0
The 8-bit RESET register provides the software with the ability to reset the UART(s) when there is a need.
Each bit is self-resetting after it is written a logic 1 to perform a reset to that channel. All registers in that
channel will be reset to the default condition, see Table 19 for details. As an example, bit-0 =1 resets UART
channel 0 with bit-7=1 resets channel 7.
3.1.6 SLEEP [7:0] (default 0x00)
The 8-bit Sleep register enables each UART separately to enter Sleep mode. Sleep mode reduces power
consumption when the system needs to put the UART(s) to idle. The UART enters sleep mode when there is
no interrupt pending. When all 8 UARTs are put to sleep, the on-chip oscillator shuts off to further conserve
power. In this case, the octal UART is awaken by any of the UART channel on from a receive data byte or a
change on the serial port. The UART is ready after 32 crystal clocks to ensure full functionality. Also, a special
interrupt is generated with an indication of no pending interrupt. Logic 0 (default) and logic 1 disable and
enable sleep mode respectively.
SLEEP Register
Individual UART Channel Sleep Enable
Ch-7 Ch-6 Ch-5 Ch-4 Ch-3 Ch-2 Ch-1 Ch-0
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
3.1.7 Device Identification and Revision
There are 2 internal registers that provide device identification and revision, DVID and DREV registers. The 8-
bit content in the DVID register provides device identification. A return value of 0x28 from this register indicates
the device is a XR16L788. The DREV register returns a 8-bit value of 0x01 for revision A, 0x02 for revision B
and so on. This information is very useful to the software driver for identifying which device it is communicating
with and to keep up with revision changes.
3.1.7.1 DVID [7:0] (default 0x28)
Device identification for the type of UART. The upper nibble indicates it is a XR16L78x series with lower nibble
indicating the number of channels.
Examples:
XR16L788 = 0x28
XR16L784 = 0x24
3.1.7.2 DREV [7:0] (default (0x01)
Revision number of the XR16L788. A 0x01 represents "revision-A" with 0x02 for rev-B and so forth.
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