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MC13192EVB Reference Manual, Rev. 1.2
Freescale Semiconductor
4-1
Chapter 4
PCB and MC13192EVB Interfaces
The EVB can communicate with the Test Tools either through the USB or RS-232 port.
4.1
USB Interface
The MCU does not contain a dedicated USB port. To support USB, an all in one IC is used. This IC
interfaces between the UART and the USB port on a personal computer (PC). The FTDI company
manufactures an IC (FT232BM) IC105 on the MC13192EVB, which fulfils this requirement and requires
just a few external components. A simple setup requires only 11 components and that includes the USB-b
connector. R120 and R121 act as the driver output impedance of 27 Ohms on the USBDP and the USBDM
pins. R122 (1.5 kohm) controls the power state of the USB port (suspend and other states).
IC105 is clocked by its own oscillator. A 6 MHz ceramic resonator is used which is multiplied up to 8 times
depending on the usage internal in IC105. A ceramic resonator was selected. IC105 is wired to
microcontroller SCI2, with 4 connections:
1. TXD
2. RXD
3. /RTS
4. /CTS
IC105 is supplied from the USB port. The voltage level on the UART of IC105 must comply with the
voltage level of the MC9S08GT60. This is accomplished by supplying VCC_IO with 3.0 V. The USB port
from either a PC or HUB must be able to supply the MC13192EVB including IC105. The EVB can be
supplied from either the USB or the DC adapter. The design supports an external EEPROM. When using
the EEPROM, a chosen vendor ID can be displayed in the system tool.
4.2
RS-232 Interface
The RS-232 can be used as an alternative interface to the MC13192EVB. A level shifter made by Maxim,
(MAX3318E) is used as the interface between the MC9S08GT60 and the PC. The Maxim IC only requires
four capacitors to generate the RS-232 compliant signal levels.
IC104 is wired to the MCU at SCI1, with 4 connections:
1. TXD
2. RXD
3. /RTS
4. /CTS
IC104 is supplied with 3.0 V from the on board LDO, IC106.
Содержание FREESCALE MC13192
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Страница 10: ...Safety Information MC13192EVB Reference Manual Rev 1 2 1 2 Freescale Semiconductor...
Страница 18: ...System Overview MC13192EVB Reference Manual Rev 1 2 2 8 Freescale Semiconductor...
Страница 32: ...RF Front End MC13192EVB Reference Manual Rev 1 2 3 14 Freescale Semiconductor...
Страница 34: ...PCB and MC13192EVB Interfaces MC13192EVB Reference Manual Rev 1 2 4 2 Freescale Semiconductor...