Chapter 14 Serial Communication Interface (S12SCIV6)MC9S12ZVMB Family Reference Manual Rev. 1.3NXP Semiconductors 485Table 14-4. SCICR1 Field DescriptionsField Description7LOOPSLoop Select Bit — LOOPS enables loop operation. In loop operation, the RXD pin is disconnected from the SCIand the transmitter output is internally connected to the receiver input. Both the transmitter and the receiver mustbe enabled to use the loop function.0 Normal operation enabled1 Loop operation enabledThe receiver input is determined by the RSRC bit.6SCISWAISCI Stop in Wait Mode Bit — SCISWAI disables the SCI in wait mode.0 SCI enabled in wait mode1 SCI disabled in wait mode5RSRCReceiver Source Bit — When LOOPS = 1, the RSRC bit determines the source for the receiver shift registerinput. See Table 14-5.0 Receiver input internally connected to transmitter output1 Receiver input connected externally to transmitter4MData Format Mode Bit — MODE determines whether data characters are eight or nine bits long.0 One start bit, eight data bits, one stop bit1 One start bit, nine data bits, one stop bit3WAKEWakeup Condition Bit — WAKE determines which condition wakes up the SCI: a logic 1 (address mark) in themost significant bit position of a received data character or an idle condition on the RXD pin.0 Idle line wakeup1 Address mark wakeup2ILTIdle Line Type Bit — ILT determines when the receiver starts counting logic 1s as idle character bits. Thecounting begins either after the start bit or after the stop bit. If the count begins after the start bit, then a string oflogic 1s preceding the stop bit may cause false recognition of an idle character. Beginning the count after thestop bit avoids false idle character recognition, but requires properly synchronized transmissions.0 Idle character bit count begins after start bit1 Idle character bit count begins after stop bit1PEParity Enable Bit — PE enables the parity function. When enabled, the parity function inserts a parity bit in themost significant bit position.0 Parity function disabled1 Parity function enabled0PTParity Type Bit — PT determines whether the SCI generates and checks for even parity or odd parity. With evenparity, an even number of 1s clears the parity bit and an odd number of 1s sets the parity bit. With odd parity, anodd number of 1s clears the parity bit and an even number of 1s sets the parity bit.0 Even parity1 Odd parityTable 14-5. Loop FunctionsLOOPS RSRC Function0 x Normal operation1 0 Loop mode with transmitter output internally connected to receiver input1 1 Single-wire mode with TXD pin connected to receiver input
