Rev 6.0
24
User Guide
Features Configuration and Limitations
Additionally, all HL6 and HL8 GPIOs have an output voltage of 1.8 V. To compensate for this, level
shifters are incorporated into the Q26 Carrier Board to match the Q26
module’s GPIO output voltage.
The level shifter used in the Q26 Carrier Board contains an auto-sense translator which quickly
transforms an input driver to an output driver and vice versa. The input driver to the auto-sense
translator should be capable of driving 2 mA of peak output current for proper operation. Note that
although the peak current from the input signal is relatively large, the average current is small and
consistent with a standard CMOS input stage.
4.1.3.
Serial Interface
Q26 modules support two serial interfaces
– SPI and I
2
C. However, both serial interfaces are
controlled by the Open AT Application Framework which is not supported by the HL6 and HL8
modules; SPI and I
2
C buses are not supported in the Q26 Carrier Board.
4.1.4.
Parallel Interface
The parallel interface of the Q26 is controlled by the Open AT Application Framework, which is not
supported by the HL6 and HL8 modules; parallel interface is not supported in the Q26 Carrier Board.
4.1.5.
Keyboard Interface
The keyboard interface of the Q26 is controlled by the Open AT Application Framework, which is not
supported by the HL6 and HL8 modules; keyboard interface is not supported in the Q26 Carrier
Board.
4.1.6.
Main Serial Link (UART1)
The main serial link (UART1) is used for communication between the Q26 Carrier board and a PC or
host processor. It consists of a flexible 8-wire serial interface that complies with the RS-232 interface.
The UART1 voltage level of the HL6 and HL8 modules (1.8 V) is different from that of the Q26
modules (2.8 V). To ensure that UART is fully compatible, an 8-bit voltage level shifter is added in the
Q26 Carrier Board to match the Q26
module’s 2.8 V voltage and also remain 3.3 V tolerant.
4.1.7.
Auxiliary Serial Link (UART2)
Although Q26 modules support an auxiliary serial link (UART2) interface, this interface is not
supported by the HL6 and HL8 modules and so is also not supported in the Q26 Carrier Board.
4.1.8.
SIM Interface
A fully compatible 1.8V and 3V SIM card interface is available on the Q26 Carrier Board.
