User's Manual

PMAC2 PCI Hardware Reference Manual
4 Hardware Setup
In order to change the state of the card between use of internal clock and use of external clock, the card
must be re-initialized (either powered up with jumper E3 on, or given the $$$*** command) with
jumper E1 in the new state. Before the card is reset again, a SAVE command must be issued to store the
new internal settings.
CPU Frequency Control Jumpers
If variable I46 is set to the default value of zero, jumpers E2 and E4 on the base PMAC2 PCI board
control the frequency at which the CPU will operate (or attempt to operate). Generally this will be the
highest frequency at which the CPU is rated to operate.
• If jumpers E2 and E4 are both OFF, the CPU will operate at a 40MHz frequency.
• If E2 is ON and E4 is OFF, the CPU will operate at a 60MHz frequency.
• If E2 is OFF and E4 is ON, the CPU will operate at an 80MHz frequency.
• If I46 is set to a value greater than zero, E2 and E4 are not used. The CPU frequency is set to 10MHz
(I46+1)
Re-Initialization Jumper
If E3 is off during power-up/reset, the controller will load its last saved set-up parameters from flash
memory into active memory. This is the setting for normal operation.
If E3 is on during power-up/reset, the controller will load its factory-default set-up parameters from
firmware into active memory. Generally, this is done only if communications cannot be established with
the card when it comes up in normal operational mode.
Encoder Sample Clock Source Jumpers
Jumpers E13 and E14 control the source of the SCLK encoder-sampling clock for each servo IC. The
default setting no jumper installed means that the SCLK signal comes from the servo IC and is output on
the JMACH connectors. This setting is suitable for all but a few very special applications.
Serial Port Selection Jumper
Jumpers E17 and E18 control which serial-port connector is used. If E17 and E18 connect their pins 1
and 2, the 10-pin RS-232 port connector J5 is used. If E17 and E18 connect their pins 2 and 3, the 26-pin
RS-422 port connector J5A is used. The RS-422 port must be used if several cards are to be daisy-
chained together on a single multi-drop cable.
Output Disable State Jumpers
Jumpers E111 through E118 control the hardware state of the digital command output signals for each
channel when the amplifier enable signal for that channel is in the disable state (false). Jumper E11n (n =
1 to 8) controls the output signals for channel n on the board.
If E11n is off (default), the command output signals for channel n are still active when the amplifier
enable signal is in the disable state. The Turbo PMAC software should be commanding a net zero
command to be output on these signals and the amplifier enable signal should be used by the amplifier so
that no command output will cause action if it is receiving a disable signal. The off setting should be used
when DAC output format is selected for the channel.
If E11n is on, the command output signals for channel n are tri-stated when the amplifier-enable signal is
in the disable state. This setting is used only with direct-PWM power-block amplifiers that do not use
amplifier enable to gate the PWM signals, and in which the zero-command format of 50% top on-time,
and 50% bottom on-time cannot be tolerated in the disable state.