Operating instructions

Controller Board 5-5
The OMAP processor (U1000), which consists of an ARM and DSP core, needs three clocks for
operation: a 32.768kHz square-wave, a 12MHz sine-wave, and a 16.8MHz square-wave clock.
The 16.8MHz clock source is provided from the Trident TCXO routes to a squarer-circuit (U1006) and
feed to EXT_CLK (U1000 pin N18).
The 32.768kHz clock is generated by the MAKO crystal (Y3000) oscillator, converted to a gated clock
by U3003 and U3004 circuitry. It is then directly fed to OMAP CLK32_IN (U1000 pin P13). The OMAP
processor needs the 32.768kHz to determine the input reference clock applied to OSC_IN (U1000 pin
Y2). Without this 32kHz clock, the OMAP will potentially program all the wrong dividers for USB and
UART booting. External pull-up on OSC32K_IN (U1000 pin V13) and grounding both OSC32K_OUT
(pin AA13) and VSS_11 (pin Y13) indicates that an external 32kHz clock is used.
The 12MHz sine-wave is the main system reference clock for the OMAP which all the internal clocks
are derived from.
The 24.576MHz crystal (Y3001) oscillator is the reference clock for MAKO CODEC and SSI clock. `
2.3 Serial Peripheral Interface (SPI)
Figure 5-4 illustrates the controller SPI used throughout the radio.
Figure 5-4: SPI Connections
The OMAP processor (U1000) has two SPI busses that it uses to communicate with the various
peripheral IC’s. The first is the High Performance Data (HPD) SPI bus and the second is the multi-
media card (MMC) SPI.
HPD SPI
TRIDENT
U001
1.8V
CEX
SPI_DW
SPI_DR
SPI_CLK
ABACUS III
U600
PE
PD
DOUTB
PC
MAKO
U3000
SPI_CS
SPI_CLK
SPI_DO
GPIO_44 (P15)
SPIF.DOUT (W21)
SPIF.DIN (U18)
SPIF.SCK (U19)
GPIO_9 (Y8)
GPIO_58 (R11)
SPI_DI
OMAP1710
U1000
MMC1 SPI
SPI.CS1 (P19)
SPI.CLK (M14)
MMC.CMD (P11)
SPI.RDY (R18)
SPI.CS2 (P20)
SPI.CS3 (P18)
1.8V
1.8V
47K
1.8V
SPI_CLK
SPI_MOSI
SPI_MISO
THK_CE
MAKO_CE
ABACUS3_CE
R3023