Motorola ASTRO XTS 5000 Detailed Service Manual page 60

Theory of Operation
: VOCON Board 3-21
Serial Audio CODEC Port (SAP)
The Serial Audio CODEC Port (SAP) module is the DSP's serial synchronous interface (SSI) to the
audio CODEC on the GCAP II IC. However, In NNTN5567, the audio CODEC is on the MAKO IC.
The SAP also interfaces with the encryption module.
The SAP interface consists of four signals including the SAP clock line pin SCKA (component R405
or R572 (for NNTN5567) ), the SAP frame sync line pin SC2A (component R406 or R573 (for
NNTN5567) ), the SAP receive data line pin SRDA (component R402), and the transmit data line pin
STDA (component R403). On the NTN9564, NNTN4563, and NNTN4819 VOCON boards, the SAP
clock is generated by the Flipper IC U301, and is a 520 kHz, 3 V peak-to-peak square wave. The
SAP frame sync signal is also generated by the Flipper IC, and is an 8 kHz, 3 V peak-to-peak square
wave.
On NNTN5567 Vocon board, the SAP clock is generated by the MAKO IC (U501) and is a 512 kHz,
2.9V peak-to-peak wave. The SAP frame sync signal is generated by the MAKO IC U501, and is an
8kHz, 2.9V peak-to-peak square wave.
On the NNTN4717 VOCON board, the SAP clock is generated by the dual-core processor U401,
and is a 256 kHz, 2.9 V peak-to-peak square wave. The SAP frame sync signal is generated by the
dual-core processor U401, and is an 8 kHz, 2.9 V peak-to-peak square wave.
Universal Serial Bus (USB)
The Patriot IC USB peripheral, shared by the MCU and the DSP, provides the required buffering and
protocol to communicate on the Universal Serial Bus. The Patriot IC supports USB slave
functionality.
For receive data, the USB differentially decoded data comes from the Flipper IC URXD_RTS pin into
the Patriot URTS1 pin, while the single-ended USB data positive signal goes to pin PA2_USB_VPIN,
and the single-ended USB data minus signal goes to pin URXD1. The two data lines are used to
detect the single-ended zero state.
On the NNTN5567 VOCON board, the receive data path is routed from the MAKO ICs (U501)
integrated USB transceiver. Single ended positive data is generated at U501 pin B9 and is sent to
the Partriot PA2_USB_VPIN pin. USB data minus comes from U501 pin C9 and is sent to URXD1 of
the Patriot.
For transmit data, the USB data comes out of the Patriot IC UTXD1 pin and goes to either the Flipper
IC or MAKO IC (NNTN5567) TXD_USB_VPO pin. The USB transmit single-ended zero signal is
generated from the Patriot IC PC0_USB_VMOUT pin.
General-Purpose Input/Output (GPIO) Module
The General-Purpose Input/Output (GPIO) module is shared by the MCU and the DSP. This module
consists of four 16-pin bi-directional ports and a 15 pin bi-directional port. While some of the pins on
these ports are being used for other functions (UART, SPI, SAP, BBP, and Interrupt pins), the
remaining pins can be programmed to become GPIOs that can be used by either the DSP or the
MCU. Each GPIO pin has up to 8 alternate output functions and up to 4 alternate input functions.
This allows for the GPIO pins to be routed internally to pertinent Patriot IC modules. Additionally, the
GPIO module adds selectable edge-triggered or level-sensitive interrupt functionality to the GPIO
pins. Some examples of GPIO pins include the Audio PA control signals (EXT_SPKR_SEL,
AUDIO_PA_EN, and AUDIO_MODE_SEL), the EEPOT control signals (EEPOT_INC*,
EEPOT_U_D*, EEPOT_CS*, and EEPOT_CS_EXT*), and the LED control signals (RED_LED and
GREEN_LED).
6881094C31-E November 16, 2006