Specifications
405GP – Power PC 405GP Embedded Processor
AMCC 55
Revision 2.01 – January 6, 2005
Data Sheet
Strapping
When the SysReset input is driven low by an external device (system reset), the state of certain I/O pins is read to
enable default initial conditions prior to PPC405GP start-up. The actual capture instant is the nearest SysClk edge
before the deassertion of reset. These pins must be strapped using external pull-up (logical 1) or pull-down
(logical 0) resistors to select the desired default conditions. The recommended pull-up is 3kΩ to +3.3V or 10kΩ to
+5V. The recommended pull-down is 1KΩ to GND. These pins are use for strap functions only during reset. They
are used for other signals during normal operation. The following table lists the strapping pins along with their
functions and strapping options. The pin for the 456-ball package is listed first (for example, AF3), followed by the
corresponding pin for the 413-ball package (for example, U8), which appears as AF3/U8. The signal names
assigned to the pins for normal operation follow the pin numbers.
PPC405GP Strapping Pin Assignments (Part 1 of 2)
Function Option Ball Strapping
PLL Tuning
1
for 6 ≤ M ≤ 7 use choice 3
for 7 < M
≤ 12 use choice 5
for 12 < M
≤ 32 use choice 6
AF3/U8
UART0_Tx
AF2/T8
UART0_DTR
AD16/AB15
UART0_RTS
Choice 1; TUNE[5:0] = 010001 0 0 0
Choice 2; TUNE[5:0] = 111011 0 0 1
Choice 3; TUNE[5:0] = 010011 0 1 0
Choice 4; TUNE[5:0] = 111101 0 1 1
Choice 5; TUNE[5:0] = 010101 1 0 0
Choice 6; TUNE[5:0] = 010110 1 0 1
Choice 7; TUNE[5:0] = 111110 1 1 0
Choice 8; TUNE[5:0] = 100100 1 1 1
PLL Forward Divider
2
D16/A17
DMAAck0
B15/B14
DMAAck1
Bypass mode 0 0
Divide by 3 0 1
Divide by 4 1 0
Divide by 6 1 1
PLL Feedback Divider
2
B14/A15
DMAAck2
C12/A8
DMAAck3
Divide by 1 0 0
Divide by 2 0 1
Divide by 3 1 0
Divide by 4 1 1
PLB Divider from CPU
2
P25/R23
EMCTxD3
L24/J22
EMCTxD2
Divide by 1 0 0
Divide by 2 0 1
Divide by 3 1 0
Divide by 4 1 1
OPB Divider from PLB
2
L25/K21
EMCTxD1
J26/F22
EMCTxD0
Divide by 1 0 0
Divide by 2 0 1
Divide by 3 1 0
Divide by 4 1 1