PowerPC 405CR Embedded Controller Data Sheet
Signal Functional Description (Part 3 of 6)
Multiplexed signals are shown in brackets following the first signal name assigned to each multiplexed ball.
Notes:
1. Receiver input has hysteresis
2. Must pull up (recommended value is 3kΩ to 3.3V, 10kΩ to 5V)
3. Must pull down (recommended value is 1kΩ)
4. If not used, must pull up (recommended value is 3kΩ to 3.3V)
5. If not used, must pull down (recommended value is 1kΩ)
6. Strapping input during reset; pull-up or pull-down required
Signal Name
Description
I/O
Type
Notes
External MASTER Peripheral Interface
Peripheral clock to be used by an external master and by
synchronous peripheral slaves
5V tolerant
3.3V LVTTL
PerClk
ExtReset
HoldReq
HoldAck
ExtReq
ExtAck
O
O
I
Peripheral reset to be used by an external master and by
synchronous peripheral slaves
5V tolerant
3.3V LVTTL
Hold Request, used by an external master to request ownership
of the peripheral bus
5V tolerant
Rcvr
1, 5
6
Hold Acknowledge, used by the PPC405CR to transfer
ownership of peripheral bus to an external master
5V tolerant
3.3V LVTTL
O
I
ExtReq is used by an external master to indicate it is prepared to
transfer data
5V tolerant
Rcvr
1, 4
6
ExtAck is used by the PPC405CR to indicate that a data transfer
occurred.
5V tolerant
3.3V LVTTL
O
I
Used by an external master to indicate the priority of a given
transfer (0 = high, 1 = low)
5V tolerant
Rcvr
HoldPri
BusReq
PerErr
1, 4
Used when the PPC405CR needs to regain control of peripheral
interface from an external Master
5V tolerant
3.3V LVTTL
O
I
Used as an input used to record external Master errors and
external slave peripheral errors
5V tolerant
Rcvr
1, 5
1, 4
Internal Peripheral Interface
Serial Clock used to provide an alternative clock to the internally
generated serial clock. Used in cases where the allowable
internally generated baud rates are not satisfactory. This input
can be individually connected to either UART.
5V tolerant
3.3V LVTTL
UARTSerClk
I
5V tolerant
3.3V LVTTL
UART0_Rx
UART0_Tx
UART0 Serial Data In
I
O
I
1, 4
6
5V tolerant
3.3V LVTTL
UART0 Serial Data Out
UART0 Data Carrier Detect
UART0 Data Set Ready
UART0 Clear To Send
5V tolerant
3.3V LVTTL
UART0_DCD
UART0_DSR
UART0_CTS
UART0_DTR
UART0_RTS
1, 4
1, 4
1, 4
6
5V tolerant
3.3V LVTTL
I
5V tolerant
3.3V LVTTL
I
5V tolerant
3.3V LVTTL
UART0 Data Terminal Ready
UART0 Request To Send
O
O
5V tolerant
3.3V LVTTL
6
5V tolerant
3.3V LVTTL
Rcvr
UART0_RI
UART0 Ring Indicator
I
1, 4
26
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