Zilog Z80230 Manuel d'utilisateur Page 105

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 394
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 104
SCC/ESCC
User Manual
UM010903-0515 Data Communication Modes
98
the state of WR7' D3. The RCA bit is set if there is at least one byte available, regardless of the
status of WR7' bit D3.
This is the initialization sequence for the receiver in Asynchronous mode. First, WR4 selects the
mode, then WR3 and WR5 select the various options. At this point, the other registers should be
initialized as necessary. When all of this is complete, the receiver may be enabled by setting bit D0
of WR3 to 1.
See The Receiver Interrupt on page 45 for more details on receive interrupts.
Asynchronous Initialization
The initialization sequence for Asynchronous mode is listed in Table . All of the SCC’s registers
should be re-initialized after a channel or hardware reset. Also, WR4 should be programmed first
after a reset.
At this point, the other registers should be initialized according to the hardware design such as
clocking, I/O mode, etc. When this is completed, the transmitter is enabled by setting WR5 bit D3
to 1 and the receiver is enabled by setting WR3 bit D0 to 1.
Byte-Oriented Synchronous Mode
The SCC supports three byte-oriented synchronous protocols. They are: monosynchronous, bisyn-
chronous, and external synchronous.
Initialization Sequence Asynchronous Mode
Reg Bit No Description
WR9 6, 7 Hardware or channel Reset
WR4 3, 2 Select Async Mode and the
number of stop bits*
0, 1 Select parity*
6, 7 Select clock mode*
WR3 7, 6 Select number of receive bits per
character
5 Select Auto Enables Mode*
WR5 6, 5 Select number of bits/char for
transmitter
1 Select modem control (RTS)
Note: * Initializes transmitter and receiver simultaneously.
Vue de la page 104
1 2 ... 100 101 102 103 104 105 106 107 108 109 110 ... 393 394

Commentaires sur ces manuels

Pas de commentaire