HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 153

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

Bit 7 (UDRN: Underrun Error): Indicates whether or not an underrun error has occurred in byte
or bit synchronous mode. (In asynchronous mode, underrun errors do not occur.) This bit is
cleared when 1 is written to this bit position.
Bit 6 (IDL: Transmitter Idle Status): Indicates whether or not the MSCI transmitter is in idle
state. This bit is cleared when the transmit data is written to the transmit buffer.
Bit 5 (CLMD: Two-Clock Missing Detection): Indicates the detection of two missing clock
transitions in byte or bit synchronous mode when the FM codes and ADPLL are used. This occurs
when no level transition on the RXD line is detected in the search window twice in a row (two
clock cycles). If this bit is set to 1, the ADPLL automatically enters search mode.
Bit 4 (SYNCD/FLGD: SYN Pattern Detection/Flag Detection): Indicates whether or not
synchronization has been established in byte or bit synchronous mode. This bit is cleared when 1
is written to this bit position.
Asynchronous mode
Reserved. This bit always reads 0 and can be set to 0 or 1.
Byte synchronous/Bit synchronous mode
UDRN = 0:
UDRN = 1:
Asynchronous/Byte synchronous/Bit synchronous mode
IDL = 0:
IDL = 1:
Asynchronous mode
Reserved. The value of this bit is undefined when read, and must be set to 0.
Byte synchronous/Bit synchronous mode
Reserved. The value of this bit is undefined when read, and must be set to 0.
CLMD = 0:
CLMD = 1:
Asynchronous mode
Reserved. This bit always reads 0 and can be set to 0 or 1.
Byte synchronous mode
SYNCD = 0: Indicates that synchronization has not been established
SYNCD = 1: Indicates that synchronization has been established (SYN pattern detection in
mono-sync or bi-sync mode, or by the SYNC line input in external synchronous mode)
Bit synchronous mode
FLGD = 0:
FLGD = 1:
Indicates that no underrun error has occurred
Indicates that an underrun error has occurred
Indicates that the transmitter is not in idle state
Indicates that the transmitter is in idle state
Indicates that missing level transitions have not been detected
Indicates that missing level transitions have been detected
Indicates that synchronization has not been established
Indicates that synchronization has been established (flag pattern detection)
Rev. 0, 07/98, page 137 of 453