CR16MCS9VJE8 National Semiconductor, CR16MCS9VJE8 Datasheet - Page 68

• Manufacturer Part Number: CR16MCS9VJE8
• Description: 16-Bit Microcontroller IC
• Manufacturer: National Semiconductor

Specifications of CR16MCS9VJE8

• Controller Family/series: CR16X
• Core Size: 16 Bit
• Program Memory Size: 64K X 8 Flash
• Digital Ic Case Style: PQFP
• No. Of Pins: 80
• Mounting Type: Surface Mount
• Clock Frequency: 25MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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If a new shift process starts before MWDAT was written, i.e.,
while MWDAT does not contain any valid data, and the “Echo
Enable” (MECH) bit is set to 1, the data received from MDO-
DI is transmitted on MDIDO in addition to being shifted to
MWDAT. If the MECH bit is cleared to 0, the data transmitted
on MDIDO is the data held in the MWDAT register, regard-
less of its validity. The master may negate the MCS signal to
synchronize the bit count between the master and the slave.
In the case that the slave is the only slave in the system, MCS
can be tied to V
17.4
An interrupt is generated in any of the following cases:
Figure30 illustrates the various interrupt capabilities of this
module.
— When the read buffer is full (MRBF=1) and the “Enable
— Whenever the shifter is not busy, i.e. the MBSY bit is
— When an overrun condition occurs (MOVR is set to 1)
MOVR = 1
MRBF = 1
MBSY = 0
Interrupt for Read” bit is set (MEIR=1).
cleared (MBSY=0) and the “Enable Interrupt for Write”
bit is set (MEIW=1).
and the “Enable Interrupt on Overrun” bit is set
(MEIO=1). This usage is restricted to master mode.
Data Out
Data In
MSKn
INTERRUPT GENERATION
Figure 30. MWSPI Interrupts
SS
MEIW
.
MEIO
MEIR
msb
msb
msb-1
msb-1
Figure 29. Alternate Mode, MIDL Bit = 1
msb-2
Interrupt
msb-2
MWSPI
68
17.5
The software interacts with the MICROWIRE interface by ac-
cessing the MICROWIRE registers. There are five such reg-
isters:
17.5.1
The MWDAT register is a word-wide, read/write register used
to transmit and receive data through the MDODI and MDIDO
pins. Figure31 shows the hardware structure of the register.
— MICROWIRE Data Register (MWDAT)
— MICROWIRE Control Register (MWCTL)
— MICROWIRE Status Register (MWSTAT)
MICROWIRE INTERFACE REGISTERS
MICROWIRE Data Register (MWDAT)
Bit 1
Bit 1
Bit 0 (lsb)
Bit 0 (lsb)
Shift Out
End of Transfer
Sample Point