m37516e6hp Renesas Electronics Corporation., m37516e6hp Datasheet - Page 25

• Manufacturer Part Number: m37516e6hp
• Description: Single-chip 8-bit Cmos Microcomputer
• Manufacturer: Renesas Electronics Corporation.

7516 Group
(2) Asynchronous Serial I/O (UART) Mode
Clock asynchronous serial I/O mode (UART) can be selected by
clearing the serial I/O1 mode selection bit (b6) of the serial I/O1
control register to “0”.
Eight serial data transfer formats can be selected, and the transfer
formats used by a transmitter and receiver must be identical.
The transmit and receive shift registers each have a buffer, but the
Fig. 20 Block diagram of UART serial I/O1
Rev.1.01
P2
P 2
P 2
Jul 01, 2003
6
4
5
/S
/ R
/ T
CLK
X
X
X
D
I N
D
S T d e t e c t o r
BRG count source selection bit
1 / 4
page 23 of 89
Character length selection bit
Character length selection bit
7 b i t s
8 b i t s
S e r i a l I / O 1 s y n c h r o n o u s c l o c k s e l e c t i o n b i t
O E
A d d r e s s 0 0 1 8
P E FE
R e c e i v e b u f f e r r e g i s t e r
R e c e i v e s h i f t r e g i s t e r
F r e q u e n c y d i v i s i o n r a t i o 1 / ( n + 1 )
S T / S P / P A g e n e r a t o r
D a t a b u s
D a t a b u s
1 6
B a u d r a t e g e n e r a t o r
T r a n s m i t b u f f e r r e g i s t e r
Transmit shift register
SP detector
A d d r e s s 0 0 1 C
Address
Serial I/O1 control register
two buffers have the same address in memory. Since the shift reg-
ister cannot be written to or read from directly, transmit data is
written to the transmit buffer register, and receive data is read
from the receive buffer register.
The transmit buffer register can also hold the next data to be
transmitted, and the receive buffer register can hold a character
while the next character is being received.
1/16
1 6
C l o c k c o n t r o l c i r c u i t
0018
16
Receive buffer full flag (RBF)
Receive interrupt request (RI)
T r a n s m i t i n t e r r u p t s o u r c e s e l e c t i o n b i t
Serial I/O1 status register
Address 001A
1/16
Transmit buffer empty flag (TBE)
T r a n s m i t s h i f t c o m p l e t i o n f l a g ( T S C )
U A R T c o n t r o l r e g i s t e r
T r a n s m i t i n t e r r u p t r e q u e s t ( T I )
16
Address
A d d r e s s 0 0 1 B
0019
16
1 6