M16C User Manual.pdf

SIM interfaceMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER2.5.6 Clock Signals in used for the SIM InterfaceIn conforming to the SIM interface, the UART clock signal within the SIM card needs to conform to theUART2 clock signal within the microprocessor. Two examples are given here as means of generating aUART2 clock signal within the microprocessor.* In the case of setting a value equal to or less than (1/256 X 1/16) in the division rate of UART2 clockChoose f1 for the UART’s source clock signal and set an optional value in the bit rate generator.* In the case of setting a value equal to or greater than (1/256 X 1/16) in the division rate of UART2 clockSet the bit rate generator to "0", turn the source clock signal to timer output and set an optional valuein the timer.Let F be the clock signal within the SIM card and D be the bit rate adjustment factor, then the formula forthe UART clock signal becomes as follows. Figure 2.5.20 shows an example of connection.• In the case of setting a value equal to or less than (1/256 X 1/16) in the division rate of UART2 clockUART2 clock signal within microprocessor = UART clock within SIM card11 1f1 x x = f1 x x flip-flop xBit rate generator + 1 16Timer Ai counter + 11F/DLet XIN = 16 MHz, timer Ai counter = 1, F = 372, and D = 1, then the value to be set in the bit rategenerator becomes11 1 116 x x =16 X x xBit rate generator + 1 16 2 21372/1Bit rate generator = 92Table 2.5.8 shows an example of setting in the UART2 bit rate generator.• In the case of setting a value equal to or greater than (1/256 X 1/16) in the division rate of UART2 clockUART2 clock signal within microprocessor = UART clock within SIM card111f1 x x flip-flop x xTimer Aj counter + 1 Bit rate generator + 1 1611= f1 x x flip-flop xBit rate generator + 1F/DLet XIN= 16 MHz, timer Ai counter = 3, bit rate generator = 0, F = 1860, and D = 1, then the value to beset in the timer Aj counter becomes11 1 11 116 x x x x =16 x x xTimer Aj counter + 1 2 0 + 1 16 3 + 1 211860/1Timer Aj counter = 464Table 2.5.9 shows an example of setting in the timer Aj counter.374