NS32FX100-15 Datasheet, PDF (25/94 Pages) National Semiconductor (TI) – System Controller

2 0 Architecture (Continued)
8 The peak detector window may be used to disable the
ABC circuit outside the programmed window The ac-
tive video window and the peak detector window are
configured separately thus allowing a peak detector
window smaller than the active video window
9 Programming the Pixel Generator bypass control (using
SVHC BYPASS) must be accompanied by an appropri-
ate setup in the Port C control bits PCMS MS4 and
PCEN EN4
10 To prevent loss of pixels by the Bitmap Shifter the ac-
tive window should be programmed to allow the accu-
mulation of exactly 16 pixels
11 Whenever the time-slot set for the stepper motor is
reached the SMPH register in the Ports module should
be updated by software to hold the phase value of the
next change This should be done in the appropriate
interrupt handler code At the same time a different
time-slot may be set in the SMTSL to control the next
stepper motor phase
12 The NS32FX100 Scanner module should be configured
to match the requirements of the scanner device the
external analog circuit and the NS32FX100 analog cir-
cuit The NS32FX100 analog circuit requirements are
detailed in Section 4 5
13 Do not disable the Scanner Controller during Active
Window time frame
14 Access dither registers only outside the active window
2 5 PRINTER CONTROLLER (PRNTC)
2 5 1 Features
 Interfaces with a variety of Thermal Print-Head (TPH)
devices
 Programmable strobe mode strobe cycle duty cycle and
polarity
 On-Chip TPH temperature sensing circuitry
 Bitmap shift register using DMA channel 1
 Support for Laser Beam and Ink-Jet engines
(NS32FX200 only)
2 5 2 Operation
The NS32FX100 provides a complete interface to TPH de-
vices The PRNTC operates at a minimum frequency of
14 7456 MHz
This module is composed of two blocks
Printer Bitmap Shifter Block
Transfers data to the printer from memory via DMA channel
1 to the Printer Bitmap Shifter of the PRNTC from which it
is then serially shifted to the printer
The block’s output signals are
PCLK (clock)
PDO (data)
Thermal Print-Head Block
Controls signals such as strobes and stepper motor phase
signals It also features a temperature sensing circuit which
receives an indication of the TPH temperature through the
PTMP temperature sense pin and is used by software to
control the strobes ensuring that the TPH does not over-
heat
The block’s input signal is
PTMP (analog temperature)
The block’s output signals are
STB0 – 3 (TPH strobes)
2 5 2 1 Printer Bitmap Shifter Block
Data for the printer is first transferred from memory via DMA
channel 1 into a 16-bit latch in the Printer Bitmap Shifter
From this latch the data is transferred to a 16-bit shift regis-
ter from which it is serially shifted to the printer
At the beginning of the operation (when PRNTC is enabled
by setting the EPBMS bit in the MCFG register) this block
issues two consecutive DMA requests one to fill the shift
register and one to fill the latch Subsequently whenever
the shift register is empty the latch contents are transferred
to it and a new DMA transfer is requested to refill the latch
Shift direction is controlled by the SLNR bit of the Printer
Bitmap Configuration (PBCFG) register Actual bitmap shift
takes place according to the ECLK bit of the PBCFG regis-
ter using either an internal or an external clock (in the
NS32FX100 and NS32FV100 this bit is always ‘‘0’’ and the
shifting always uses an internal clock) Data is always shift-
ed out when the shifter is not empty on clock falling edge
When an internal clock is used the clock signal is high
when there is no available data to shift out
An internal clock is used for Thermal Print-Heads
An external clock is recommended for Laser Beam Printers
since video (pixels) left margin active time and polarity are
externally synchronized with the printer engine
The frequency of the external clock should be in the range
0 5 MHz to 4 MHz
2 5 2 2 Thermal Print-Head Control Block
This block generates the printer stepper motor phase sig-
nals the printer strobes and the printer interrupt Its opera-
tion is synchronized with the TCU time slots and is fully
controlled by software
Stepper Motor Controller
The stepper motor is controlled by four phases The motor
direction and speed is controlled by setting or clearing
each phase as printing progresses The motor is controlled
by setting the time-slots in which the phases should be
changed (in the PMTSL register) When the set time-slot is
reached an interrupt is generated and the phase values are
updated to the values in the phase register (PMPH) in the
Ports module
FIGURE 2-11 Bitmap Shifter Signals
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