Interface Support Section; Mako Ic U701 - Motorola XTS 2500 Service Manual

4.2-12

4.2.6.3 Interface Support Section

The interface support section includes the following:
• the MAKO IC (U701)
• the ESD protection circuitry, and
• the universal connector interface circuitry.

4.2.6.3.1 MAKO IC U701

The digital-support functions are performed by the MAKO IC. The MAKO IC is contained in a 176-pin
BGA with 0.8mm pitch solder balls. The MAKO IC is supplied with three clocks. It is supplied with a
16.8 MHz clock from the transceiver board. It uses a 32.768 kHz crystal to boot up the dual core
processor and for the real-time clock. It also uses a 24.576 MHz crystal to generate the SAP clock
and frame synchronization signals.
The MAKO IC includes that one-wire option detect support, watchdog timer, and the radio's universal
(accessory) side connector interface. It also monitors the position of the on/off switch in order to
control the power-up/power-down sequence.
4.2.6.3.1.1 Side Connector Interface, Logic Level Translation, and Boot Data Path Control
The LH Data bidirectional translation is performed internal to the MAKO IC and 3V logic level is on
MAKO pin SB96D_BDO_KF_3V.
4.2.6.3.1.2 USB Transceiver
The USB transceiver is internal to MAKO IC U701, and is capable of transmitting and receiving serial
data at a rate of 12 megabits per second. The differential USB data comes from the side connector,
through the 33-ohm resistors R837 and R838 and then to the USB1_DP and USB1_DM pins on
U701. The data will then go through some interfacing and multiplexing internal to the transceiver for
6-wire USB operation and onto the output pins. The USB receive interface through the transceiver to
the dual core processor is as follows: DP routed to USB_VPI, DM routed to URXD1_USB_VMI, and
the differentially decoded data is output on URTS1_XRXD pin.
The USB transmitter is enabled when the RS232_USB* and USB_TXENAB signals are both driven
low by the dual-core processor. The single-ended data is output from the dual-core processor on the
UTXD1_USB_VPO pin and goes to USB1_DAT_TXD on U701. The data is driven out differentially
on the USB1_DP and USB1_DM pins, which go to the side connector. The dual-core processor
sends the single-ended zero signal from pin USB_VMO to the USB1_SE0 pin on U701.
When a USB cable is attached, pin CTS_CABLE_DET_5V is driven low and goes through level
translation in U701 and the output of CTS_CABLE_DET_3V is pulsed low and sent to the dual-core
processor. This line controls the USB and RS232 modes so that the data that is on those lines are
routed to the USB transceiver when a cable is detected. If a USB cable is not detected,
CTS_CABLE_DET_3V is high, the transceiver is put in suspend mode and the DP and DM pins can
now handle 5V tolerance for RS232 mode.
4.2.6.3.1.3 One-Wire Support
New options and accessories that attach to the side connector are identified by the dual-core
processor using the One-Wire protocol. The One-Wire pin on the side connector serves as the One-
Wire data pin. This signal is connected to the ONE_WIRE_OPT pin. This pin is connected to the
dual-core processor One-wire bus ONE_WIRE_UP through the MAKO IC, U701, internal isolation
switch controlled by the SPI commands sent from the dual-core processor. This isolation is needed
to prevent possible contention on the One-Wire bus when a smart battery is attached to the radio.
February 14, 2012
UHF1 Detailed Theories of Operation: VOCON Functional Blocks
6816985H01-F