xr17c152im Exar Corporation, xr17c152im Datasheet - Page 15

• Manufacturer Part Number: xr17c152im
• Description: 5v Pci Bus Dual Uart
• Manufacturer: Exar Corporation

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REV. 1.2.0
TIMERMSB [31:24] and TIMERLSB [23:16]
TIMERMSB and TIMERLSB form a 16-bit value. The least-significant bit of the timer is being bit [0] of the
TIMERLSB with most-significant-bit being bit-7 in TIMERMSB. Notice that these registers do not hold the
current counter value when read. Reading the TIMERCNTL register will clear its interrupt. Default value is
zero (timer disabled) upon powerup and reset.
Each bit selects 8X or 16X sampling rate for that UART channel, bit-0 is channel 0. Logic 0 (default) selects
normal 16X sampling with logic one selects 8X sampling rate. Transmit and receive data rates will double by
selecting 8X.
Bits 0 to 1 of the Reset register [RESET] 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
channel 0 while bit-1=1 resets channel 1.
1.2.3
1.2.4
1.2.5
B it-15 B it-14 B it-13 B it-1 2 B it-11 B it-10
8XMODE [7:0] (default 0x00)
REGA [15:8] Reserved
RESET [23:16] - (default 0x00)
TIM E RM SB Reg ister
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
Rsvd
Rsvd
Individual UART Channel 8X Clock Mode Enable
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
1 6 -B it T im e r/C o u n te r P ro g ra m m a b le R e g iste rs
Individual UART Channel Reset Enable
Rsvd
Rsvd
B it-9 B it-8
Rsvd Rsvd Rsvd Rsvd Ch-1 Ch-0
Rsvd Rsvd Rsvd Rsvd Ch-1 Ch-0
8XM O DE Register
RESET Register
15
Table 19 on page 48
B it-7
B it-6
B it-5
TIM E RLS B Register
for details. Bit-0 =1 resets UART
B it-4
5V PCI BUS DUAL UART
B it-3
B it-2
B it-1 B it-0
XR17C152