datasheetbank_Logo
Integrated circuits, Transistor, Semiconductors Search and Datasheet PDF Download Site

MC145190F View Datasheet(PDF) - Motorola => Freescale

Part Name
Description
View to exact match
MC145190F
Motorola
Motorola => Freescale Motorola
MC145190F Datasheet PDF : 24 Pages
1 2 3 4 5 6 7 8 9 10 Next Last
PIN DESCRIPTIONS
DIGITAL INTERFACE PINS
Din
Serial Data Input (Pin 19)
The bit stream begins with the most significant bit (MSB)
and is shifted in on the low–to–high transition of CLK. The bit
pattern is 1 byte (8 bits) long to access the C or configuration
register, 2 bytes (16 bits) to access the first buffer of the R
register, or 3 bytes (24 bits) to access the A register (see
Table 1). The values in the C, R, and A registers do not
change during shifting because the transfer of data to the
registers is controlled by ENB.
CAUTION
The value programmed for the N–counter must be
greater than or equal to the value of the A–counter.
The 13 least significant bits (LSBs) of the R register are
double–buffered. As indicated above, data is latched into the
first buffer on a 16–bit transfer. (The 3 MSBs are not double–
buffered and have an immediate effect after a 16–bit trans-
fer.) The second buffer of the R register contains the 13 bits
for the R counter. This second buffer is loaded with the con-
tents of the first buffer when the A register is loaded (a 24–bit
transfer). This allows presenting new values to the R, A, and
N counters simultaneously. If this is not required, then the
16–bit transfer may be followed by pulsing ENB low with no
signal on the CLK pin. This is an alternate method of
transferring data to the second buffer of the R register (see
Figure 17).
The bit stream needs neither address nor steering bits due
to the innovative BitGrabber registers. Therefore, all bits in
the stream are available to be data for the three registers.
Random access of any register is provided. That is, the reg-
isters may be accessed in any sequence. Data is retained in
the registers over a supply range of 4.5 to 5.5 V. The formats
are shown in Figures 15, 16, and 17.
Din typically switches near 50% of VDD to maximize noise
immunity. This input can be directly interfaced to CMOS de-
vices with outputs guaranteed to switch near rail–to–rail.
When interfacing to NMOS or TTL devices, either a level
shifter (MC74HC14A, MC14504B) or pull–up resistor of 1 k
to 10 kmust be used. Parameters to consider when sizing
the resistor are worst–case IOL of the driving device, maxi-
mum tolerable power consumption, and maximum data rate.
Table 1. Register Access
(MSBs are shifted in first; C0, R0, and A0 are the LSBs)
Number
of Clocks
8
16
24
Other Values 32
Values > 32
Accessed
Register
C Register
R Register
A Register
See Figure 13
See Figures
22 – 25
Bit
Nomenclature
C7, C6, C5, . . ., C0
R15, R14, R13, . . ., R0
A23, A22, A21, . . ., A0
CLK
Serial Data Clock Input (Pin 18)
Low–to–high transitions on CLK shift bits available at
the Din pin, while high–to–low transitions shift bits from
OUTPUT A (when configured as Data Out, see Pin 16).
MOTOROLA
The 24–1/2–stage shift register is static, allowing clock
rates down to dc in a continuous or intermittent mode.
Eight clock cycles are required to access the C register.
Sixteen clock cycles are needed for the first buffer of the R
register. Twenty–four cycles are used to access the A regis-
ter. See Table 1 and Figures 15, 16, and 17. The number of
clocks required for cascaded devices is shown in Figures 24
through 26.
CLK typically switches near 50% of VDD and has a
Schmitt–triggered input buffer. Slow CLK rise and fall times
are allowed. See the last paragraph of Din for more informa-
tion.
NOTE
To guarantee proper operation of the power–on
reset (POR) circuit, the CLK pin must be held at
GND (with ENB being a don’t care) or ENB must
be held at the potential of the V+ pin (with CLK be-
ing a don’t care) during power–up. As an alterna-
tive, the bit sequence of Figure 13 may be used.
ENB
Active Low Enable Input (Pin 17)
This pin is used to activate the serial interface to allow the
transfer of data to/from the device. When ENB is in an inac-
tive high state, shifting is inhibited and the port is held in the
initialized state. To transfer data to the device, ENB (which
must start inactive high) is taken low, a serial transfer is
made via Din and CLK, and ENB is taken back high. The
low–to–high transition on ENB transfers data to the C or A
registers and first buffer of the R register, depending on the
data stream length per Table 1.
NOTE
Transitions on ENB must not be attempted while
CLK is high. This puts the device out of synchro-
nization with the microcontroller. Resynchro-
nization occurs whenever ENB is high and CLK is
low.
This input is also Schmitt–triggered and switches near
50% of VDD, thereby minimizing the chance of loading erro-
neous data into the registers. See the last paragraph of Din
for more information.
For POR information, see the note for the CLK pin.
OUTPUT A
Configurable Digital Output (Pin 16)
OUTPUT A is selectable as fR, fV, Data Out, or Port.
Bits A22 and A23 in the A register control the selection;
see Figure 16.
If A23 = A22 = high, OUTPUT A is configured as
fR. This signal is the buffered output of the 13–stage R
counter. The fR signal appears as normally low and
pulses high, and can be used to verify the divide ratio of
the R counter. This ratio extends from 5 to 8191 and is
determined by the binary value loaded into bits R0–R12
in the R register. Also, direct access to the phase detec-
tors via the REFin pin is allowed by choosing a divide
value of 1 (see Figure 17). The maximum frequency at
which the phase detectors operate is 2 MHz. Therefore,
the frequency of fR should not exceed 2 MHz.
If A23 = high and A22 = low, OUTPUT A is configured as
fV. This signal is the buffered output of the 12–stage N
counter. The fV signal appears as normally low and pulses
high, and can be used to verify the operation of the prescaler,
MC145190MC145191
9
 

Share Link: 

datasheetbank.com [ Privacy Policy ] [ Request Datasheet ] [ Contact Us ]