cp3bt13 National Semiconductor Corporation, cp3bt13 Datasheet - Page 145

• Manufacturer Part Number: cp3bt13
• Description: Cp3bt13 Reprogrammable Connectivity Processor With Bluetooth-r And Can Interfaces
• Manufacturer: National Semiconductor Corporation

20.5.2
The MWCTL1 register is a word-wide, read/write register
used to control the Microwire module. To avoid clock glitch-
es, the MWEN bit must be clear while changing the states
of any other bits in the register. At reset, all non-reserved
bits are cleared. The register format is shown below.
MWEN
SCM
15
7
EIW
Microwire Control Register (MWCTL1)
6
The Microwire Enable bit controls whether the
Microwire interface module is enabled.
0 – Microwire module disabled.
1 – Microwire module enabled.
Clearing this bit disables the module, clears
the status bits in the Microwire status register
(the BSY, RBF, and OVR bits in MWSTAT),
and places the Microwire interface pins in the
states described below.
MSK
MWCS
MDIDO
MDODI
EIR
5
Pin
SCDV
EIO
4
ECHO MOD
Master – SCIDL Bit
Slave – Input
Input
Master – Input
Slave – TRI-STATE
Master – Known value
Slave – Input
3
State When Disabled
Write
Read
DIN
2
Figure 78. MWDAT Register
MNS MWEN
MWDAT
9
1
Read Buffer
(Low Byte)
(Low Byte)
Shifter
SCIDL
8
0
145
MNS
MOD
ECHO
EIO
Read Buffer
(High Byte)
(High Byte)
Shifter
The Master/Slave Select bit controls whether
the CP3BT13 is a master or slave. When
clear, the device operates as a slave. When
set, the device operates as the master.
0 – CP3BT13 is slave.
1 – CP3BT13 is master.
The Mode Select bit controls whether 8- or 16-
bit mode is used. When clear, the device op-
erates in 8-bit mode. When set, the device op-
erates in 16-bit mode. This bit must only be
changed when the module is disabled or idle
(MWSTAT.BSY = 0).
0 – 8-bit mode.
1 – 16-bit mode.
The Echo Back bit controls whether the echo
back function is enabled in slave mode. This
bit must be written only when the Microwire in-
terface is idle (MWSTAT.BSY=0). The ECHO
bit is ignored in master mode. The MWDAT
register is valid from the time the register has
been written until the end of the transfer. In the
echo back mode, MDODI is transmitted (ech-
oed back) on MDIDO if the MWDAT register
does not contain any valid data. With the echo
back function disabled, the data held in the
MWDAT register is transmitted on MDIDO,
whether or not the data is valid.
0 – Echo back disabled.
1 – Echo back enabled.
The Enable Interrupt on Overrun bit enables
or disables the overrun error interrupt. When
set, an interrupt is generated when the Re-
ceive Overrun Error bit (MWSTAT.OVR) is set.
Otherwise, no interrupt is generated when an
overrun error occurs. This bit must only be en-
abled in master mode.
0 – Disable overrun error interrupts.
1 – Enable overrun error interrupts.
MOD
1
0
DS074
DOUT
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