Max3107 spi/i, C uart with 128-word fifos and internal oscillator – Rainbow Electronics MAX3107 User Manual
Page 43
______________________________________________________________________________________ 43
MAX3107
SPI/I
2
C UART with 128-Word FIFOs
and Internal Oscillator
Bit 7: CLKtoRTS
Set the CLKtoRTS bit to 1 to route the baud-rate generator (16x baud rate) output clock to RTS/CLKOUT. The clock
frequency is a factor of 16x, 8x, or 4x of the baud rate, depending on the BRGConfig[5:4] settings.
Bits 6 and 5: No Function
Bit 4: ExtClock
Set the ExtClock bit high to enable an external clocking source (crystal or clock generator at XIN). Set the ExtClock bit
to 0 to select the internal oscillator for clocking.
Bit 3: PLLBypass
Set the PLLBypass bit high to enable bypassing the internal PLL and predivider.
Bit 2: PLLEn
Set the PLLEn bit high to enable the internal PLL. If PLLEn is set low, the internal PLL is disabled.
Bit 1: CrystalEn
Set the CrystalEn bit high to enable the crystal oscillator. When using an external clock source at XIN, CrystalEn must
be set low.
Bit 0: IntOscEn
Set the IntOscEn bit high to enable the internal oscillator. If IntOscEn is set low, the internal oscillator is disabled.
Bit 7–0: Bit[7:0]
The RevID register indicates the revision number of the MAX3107 silicon, starting with 0xA1. This can be used during
software development.
CLKSource—Clock Source Register
RevID—Revision Identification Register
ADDRESS:
0x1E
MODE:
R/W
BIT
7
6
5
4
3
2
1
0
NAME
CLKtoRTS
—
—
ExtClock
PLLBypass
PLLEn
CrystalEn
IntOscEn
RESET
0
0
0
0
1
0
0
0
ADDRESS:
0x1F
MODE:
R
BIT
7
6
5
4
3
2
1
0
NAME
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
RESET
1
0
1
0
0
0
0
1