Mateusz Grzywacz / MMA845x

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of MMA845x by Multi-Hackers

Files at this revision

API Documentation at this revision

Revision 5:d662a7003b6f, committed 2018-01-31

Comitter:
Evan Hosseini
Date:
Wed Jan 31 10:02:14 2018 -0600
Parent:
4:4ff1650da84c
Child:
6:b6f541c91c62
Child:
7:90ce70da8673
Commit message:
Make driver thread safe by making i2c read transactions atomic

Changed in this revision

MMA845x.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/MMA845x.cpp	Mon Oct 17 08:38:38 2016 -0500
+++ b/MMA845x.cpp	Wed Jan 31 10:02:14 2018 -0600
@@ -50,7 +50,6 @@
     uint8_t i = 0;
     char reg_val[1];
 
-    _i2c->frequency(100000);
     _who_am_i = 0x00;
 
     // Reset all registers to POR values
@@ -290,8 +289,8 @@
 
     result |= _i2c->write(_i2c_addr, buf, 2);
 
-    if(result != 0) {
-        debug("MMA845x:writeRegister failed r-%d\n\r",result);
+    if (result != 0) {
+        debug("MMA845x::writeRegister failed r-%d\n\r",result);
     }
 
     return result;
@@ -303,18 +302,23 @@
     char reg_out[1];
 
     reg_out[0] = reg;
+    _i2c->lock();
+
+    // MMA8451Q expects a repeated start from the master
     result |= _i2c->write(_i2c_addr,reg_out,1,true);
 
-    if(result != 0) {
+    if (result != 0) {
         debug("MMA845x::readRegister failed write r- %d\n\r", result);
-        return result;
+        goto exit;
     }
 
     result |= _i2c->read(_i2c_addr,data,count,false);
 
-    if(result != 0) {
+    if (result != 0) {
         debug("MMA845x::readRegister failed read r-%d\n\r",result);
     }
 
+exit:
+    _i2c->unlock();
     return result;
 }